diff --git a/lib/resty/healthcheck.lua b/lib/resty/healthcheck.lua
index 89d1284a..1567cc66 100644
--- a/lib/resty/healthcheck.lua
+++ b/lib/resty/healthcheck.lua
@@ -42,6 +42,46 @@ local ngx_worker_pid = ngx.worker.pid
 local ssl = require("ngx.ssl")
 local resty_timer = require "resty.timer"
 
+local new_tab
+local nkeys
+local is_array
+
+do
+  local pcall = pcall
+  local ok
+
+  ok, new_tab = pcall(require, "table.new")
+  if not ok then
+    new_tab = function () return {} end
+  end
+
+  -- OpenResty branch of LuaJIT New API
+  ok, nkeys = pcall(require, "table.nkeys")
+  if not ok then
+    nkeys = function (tab)
+      local count = 0
+      for _, v in pairs(tab) do
+        if v ~= nil then
+          count = count + 1
+        end
+      end
+      return count
+    end
+  end
+
+  ok, is_array = pcall(require, "table.isarray")
+  if not ok then
+    is_array = function(t)
+      for k in pairs(t) do
+          if type(k) ~= "number" or math.floor(k) ~= k then
+            return false
+          end
+      end
+      return true
+    end
+  end
+end
+
 -- constants
 local EVENT_SOURCE_PREFIX = "lua-resty-healthcheck"
 local LOG_PREFIX = "[healthcheck] "
@@ -866,8 +906,42 @@ function checker:run_single_check(ip, port, hostname, hostheader)
 
   end
 
+  local req_headers = self.checks.active.headers
+  local headers
+  if self.checks.active._headers_str then
+    headers = self.checks.active._headers_str
+  else
+    local headers_length = nkeys(req_headers)
+    if headers_length > 0 then
+      if is_array(req_headers) then
+        self:log(WARN, "array headers is deprecated")
+        headers = table.concat(req_headers, "\r\n")
+      else
+        headers = new_tab(0, headers_length)
+        local idx = 0
+        for key, values in pairs(req_headers) do
+            if type(values) == "table" then
+              for _, value in ipairs(values) do
+                idx = idx + 1
+                headers[idx] = key .. ": " .. tostring(value)
+              end
+            else
+              idx = idx + 1
+              headers[idx] = key .. ": " .. tostring(values)
+            end
+        end
+        headers = table.concat(headers, "\r\n")
+      end
+      if #headers > 0 then
+        headers = headers .. "\r\n"
+      end
+    end
+    self.checks.active._headers_str = headers or ""
+  end
+
   local path = self.checks.active.http_path
-  local request = ("GET %s HTTP/1.0\r\nHost: %s\r\n\r\n"):format(path, hostheader or hostname)
+  local request = ("GET %s HTTP/1.0\r\n%sHost: %s\r\n\r\n"):format(path, headers, hostheader or hostname or ip)
+  self:log(DEBUG, "request head: ", request)
 
   local bytes
   bytes, err = sock:send(request)
@@ -1229,6 +1303,7 @@ local defaults = {
       concurrency = 10,
       http_path = "/",
       https_verify_certificate = true,
+      headers = {""},
       healthy = {
         interval = 0, -- 0 = disabled by default
         http_statuses = { 200, 302 },
@@ -1300,6 +1375,7 @@ end
 -- * `checks.active.concurrency`: number of targets to check concurrently
 -- * `checks.active.http_path`: path to use in `GET` HTTP request to run on active checks
 -- * `checks.active.https_verify_certificate`: boolean indicating whether to verify the HTTPS certificate
+-- * `checks.active.headers`: one or more lists of values indexed by header name
 -- * `checks.active.healthy.interval`: interval between checks for healthy targets (in seconds)
 -- * `checks.active.healthy.http_statuses`: which HTTP statuses to consider a success
 -- * `checks.active.healthy.successes`: number of successes to consider a target healthy
diff --git a/t/20-req-headers.t b/t/20-req-headers.t
new file mode 100644
index 00000000..3c2433e2
--- /dev/null
+++ b/t/20-req-headers.t
@@ -0,0 +1,264 @@
+use Test::Nginx::Socket::Lua 'no_plan';
+use Cwd qw(cwd);
+
+workers(1);
+
+my $pwd = cwd();
+
+our $HttpConfig = qq{
+    lua_package_path "$pwd/lib/?.lua;;";
+    lua_shared_dict test_shm 8m;
+    lua_shared_dict my_worker_events 8m;
+};
+
+run_tests();
+
+__DATA__
+
+=== TEST 1: headers: {"User-Agent: curl/7.29.0"}
+--- http_config eval
+qq{
+    $::HttpConfig
+
+    server {
+        listen 2112;
+        location = /status {
+            return 200;
+        }
+    }
+}
+--- config
+    location = /t {
+        content_by_lua_block {
+            local we = require "resty.worker.events"
+            assert(we.configure{ shm = "my_worker_events", interval = 0.1 })
+            local healthcheck = require("resty.healthcheck")
+            local checker = healthcheck.new({
+                name = "testing",
+                shm_name = "test_shm",
+                checks = {
+                    active = {
+                        http_path = "/status",
+                        healthy  = {
+                            interval = 0.1
+                        },
+                        headers = {"User-Agent: curl/7.29.0"}
+                    }
+                }
+            })
+            ngx.sleep(0.2) -- wait twice the interval
+            local ok, err = checker:add_target("127.0.0.1", 2112, nil, true)
+            ngx.say(ok)
+            ngx.sleep(0.2) -- wait twice the interval
+        }
+    }
+--- request
+GET /t
+--- response_body
+true
+--- error_log
+checking healthy targets: nothing to do
+checking healthy targets: #1
+GET /status HTTP/1.0
+User-Agent: curl/7.29.0
+Host: 127.0.0.1
+
+
+
+=== TEST 2: headers: {"User-Agent: curl"}
+--- http_config eval
+qq{
+    $::HttpConfig
+
+    server {
+        listen 2112;
+        location = /status {
+            return 200;
+        }
+    }
+}
+--- config
+    location = /t {
+        content_by_lua_block {
+            local we = require "resty.worker.events"
+            assert(we.configure{ shm = "my_worker_events", interval = 0.1 })
+            local healthcheck = require("resty.healthcheck")
+            local checker = healthcheck.new({
+                name = "testing",
+                shm_name = "test_shm",
+                checks = {
+                    active = {
+                        http_path = "/status",
+                        healthy  = {
+                            interval = 0.1
+                        },
+                        headers = {"User-Agent: curl"}
+                    }
+                }
+            })
+            ngx.sleep(0.2) -- wait twice the interval
+            local ok, err = checker:add_target("127.0.0.1", 2112, nil, true)
+            ngx.say(ok)
+            ngx.sleep(0.2) -- wait twice the interval
+        }
+    }
+--- request
+GET /t
+--- response_body
+true
+--- error_log
+checking healthy targets: nothing to do
+checking healthy targets: #1
+GET /status HTTP/1.0
+User-Agent: curl
+Host: 127.0.0.1
+
+
+=== TEST 3: headers: { ["User-Agent"] = "curl" }
+--- http_config eval
+qq{
+    $::HttpConfig
+
+    server {
+        listen 2112;
+        location = /status {
+            return 200;
+        }
+    }
+}
+--- config
+    location = /t {
+        content_by_lua_block {
+            local we = require "resty.worker.events"
+            assert(we.configure{ shm = "my_worker_events", interval = 0.1 })
+            local healthcheck = require("resty.healthcheck")
+            local checker = healthcheck.new({
+                name = "testing",
+                shm_name = "test_shm",
+                checks = {
+                    active = {
+                        http_path = "/status",
+                        healthy  = {
+                            interval = 0.1
+                        },
+                        headers = { ["User-Agent"] = "curl" }
+                    }
+                }
+            })
+            ngx.sleep(0.2) -- wait twice the interval
+            local ok, err = checker:add_target("127.0.0.1", 2112, nil, true)
+            ngx.say(ok)
+            ngx.sleep(0.2) -- wait twice the interval
+        }
+    }
+--- request
+GET /t
+--- response_body
+true
+--- error_log
+checking healthy targets: nothing to do
+checking healthy targets: #1
+GET /status HTTP/1.0
+User-Agent: curl
+Host: 127.0.0.1
+
+
+
+=== TEST 4: headers: { ["User-Agent"] = {"curl"} }
+--- http_config eval
+qq{
+    $::HttpConfig
+
+    server {
+        listen 2112;
+        location = /status {
+            return 200;
+        }
+    }
+}
+--- config
+    location = /t {
+        content_by_lua_block {
+            local we = require "resty.worker.events"
+            assert(we.configure{ shm = "my_worker_events", interval = 0.1 })
+            local healthcheck = require("resty.healthcheck")
+            local checker = healthcheck.new({
+                name = "testing",
+                shm_name = "test_shm",
+                checks = {
+                    active = {
+                        http_path = "/status",
+                        healthy  = {
+                            interval = 0.1
+                        },
+                        headers = { ["User-Agent"] = {"curl"} }
+                    }
+                }
+            })
+            ngx.sleep(0.2) -- wait twice the interval
+            local ok, err = checker:add_target("127.0.0.1", 2112, nil, true)
+            ngx.say(ok)
+            ngx.sleep(0.2) -- wait twice the interval
+        }
+    }
+--- request
+GET /t
+--- response_body
+true
+--- error_log
+checking healthy targets: nothing to do
+checking healthy targets: #1
+GET /status HTTP/1.0
+User-Agent: curl
+Host: 127.0.0.1
+
+
+
+=== TEST 5: headers: { ["User-Agent"] = {"curl", "nginx"} }
+--- http_config eval
+qq{
+    $::HttpConfig
+
+    server {
+        listen 2112;
+        location = /status {
+            return 200;
+        }
+    }
+}
+--- config
+    location = /t {
+        content_by_lua_block {
+            local we = require "resty.worker.events"
+            assert(we.configure{ shm = "my_worker_events", interval = 0.1 })
+            local healthcheck = require("resty.healthcheck")
+            local checker = healthcheck.new({
+                name = "testing",
+                shm_name = "test_shm",
+                checks = {
+                    active = {
+                        http_path = "/status",
+                        healthy  = {
+                            interval = 0.1
+                        },
+                        headers = { ["User-Agent"] = {"curl", "nginx"} }
+                    }
+                }
+            })
+            ngx.sleep(0.2) -- wait twice the interval
+            local ok, err = checker:add_target("127.0.0.1", 2112, nil, true)
+            ngx.say(ok)
+            ngx.sleep(0.2) -- wait twice the interval
+        }
+    }
+--- request
+GET /t
+--- response_body
+true
+--- error_log
+checking healthy targets: nothing to do
+checking healthy targets: #1
+GET /status HTTP/1.0
+User-Agent: curl
+User-Agent: nginx
+Host: 127.0.0.1