diff --git a/lib/active_pdftk.rb b/lib/active_pdftk.rb
index 6e1f61a..9e14400 100644
--- a/lib/active_pdftk.rb
+++ b/lib/active_pdftk.rb
@@ -4,4 +4,4 @@
 require 'active_pdftk/field'
 require 'active_pdftk/form'
 require 'active_pdftk/fdf'
-require 'active_pdftk/xfdf'
\ No newline at end of file
+require 'active_pdftk/xfdf'
diff --git a/lib/active_pdftk/call.rb b/lib/active_pdftk/call.rb
index f213eac..0f232e1 100644
--- a/lib/active_pdftk/call.rb
+++ b/lib/active_pdftk/call.rb
@@ -66,7 +66,8 @@ def initialize(args = {})
   #
   # As you know command line programs take often a bunch of arguments, in a very specific syntax. that is our case.
   # In order to call pdftk in a easy way, we build a DSL, it has a hash patern, with four keys : input, operation, output, options.
-  # an additional key +:path+ can be set to specify the path to the pdftk binary.
+  # There are two additional keys. +:path+ can be set to specify the path to the pdftk binary. 
+  # +tmpdir+ can be set to specify the path of the temp directory.
   #   :input => some_input, :operation => some_operation, :output => some_output, :options => some_options
   #
   # ===Input
@@ -184,7 +185,7 @@ def pdftk(dsl_statements = {})
       dsl_statements = @default_statements.merge(dsl_statements)
       cmd = "#{@default_statements[:path]} #{set_cmd(dsl_statements)}"
       if dsl_statements[:operation].to_s.match(/burst|unpack_files/)
-        cmd.insert(0, "cd #{Dir.tmpdir} && ")
+        cmd.insert(0, "cd #{tmpdir} && ")
       end
       Open3.popen3(cmd) do |stdin, stdout, stderr|
         if @input
@@ -196,7 +197,7 @@ def pdftk(dsl_statements = {})
         raise(CommandError, {:stderr => @error, :cmd => cmd}) unless (@error = stderr.read).empty?
       end
       if dsl_statements[:operation].to_s.match(/burst|unpack_files/) && dsl_statements[:output].nil?
-        Dir.tmpdir
+        tmpdir
       else
         @output
       end
@@ -295,6 +296,14 @@ def pdftk_version
       %x{#{@default_statements[:path]} --version 2>&1}.scan(/pdftk (\S*) a Handy Tool/).join
     end
 
+    # Return the directory to use as the temp directory
+    #
+    # @return [String]
+    #
+    def tmpdir
+      @default_statements[:tmpdir] || Dir.tmpdir
+    end
+
     # Return the path of the pdftk library if it can be located.
     #
     # @return [String, nil] return nil if the library cannot be found on the system
diff --git a/spec/active_pdftk/call_spec.rb b/spec/active_pdftk/call_spec.rb
index 89bb40a..f5068b2 100644
--- a/spec/active_pdftk/call_spec.rb
+++ b/spec/active_pdftk/call_spec.rb
@@ -6,6 +6,7 @@
     before :all do
       options = {}
       options[:path] = ENV['path'] unless ENV['path'].nil?
+      options[:tmpdir] = '/custom_temp'
       @pdftk = ActivePdftk::Call.new(options)
     end
 
@@ -13,6 +14,10 @@
       @pdftk.default_statements[:path].should_not be_nil
     end
 
+    it "should set the tmpdir" do
+      @pdftk.default_statements[:tmpdir].should == '/custom_temp'
+    end
+
     it "should check the ENV vars" do
       unless ENV['path'].nil? || ENV['version'].nil?
         ENV['path'].should_not be_nil
@@ -255,4 +260,14 @@
       end
     end
   end
+
+  context "#tmpdir" do
+    before :all do
+      @pdftk = ActivePdftk::Call.new
+    end
+
+    it "should use the system tmpdir when a tmpdir is not explicity set" do
+      @pdftk.tmpdir.should == Dir.tmpdir
+    end
+  end
 end
diff --git a/spec/active_pdftk/wrapper_spec.rb b/spec/active_pdftk/wrapper_spec.rb
index a0b7ad2..0742d9c 100644
--- a/spec/active_pdftk/wrapper_spec.rb
+++ b/spec/active_pdftk/wrapper_spec.rb
@@ -58,8 +58,8 @@ def map_output_type(output_specified)
 
     it "should pass the defaults statements to the call instance." do
       path = ActivePdftk::Call.new.locate_pdftk
-      @pdftk_opt = ActivePdftk::Wrapper.new(:path => path, :operation => {:fill_form => 'a.fdf'}, :options => { :flatten => false, :owner_pw => 'bar', :user_pw => 'baz', :encrypt  => :'40bit'})
-      @pdftk_opt.default_statements.should == {:path => path, :operation => {:fill_form => 'a.fdf'}, :options => { :flatten => false, :owner_pw => 'bar', :user_pw => 'baz', :encrypt  => :'40bit'}}
+      @pdftk_opt = ActivePdftk::Wrapper.new(:path => path, :tmpdir => '/other_tmp', :operation => {:fill_form => 'a.fdf'}, :options => { :flatten => false, :owner_pw => 'bar', :user_pw => 'baz', :encrypt  => :'40bit'})
+      @pdftk_opt.default_statements.should == {:path => path, :tmpdir => '/other_tmp', :operation => {:fill_form => 'a.fdf'}, :options => { :flatten => false, :owner_pw => 'bar', :user_pw => 'baz', :encrypt  => :'40bit'}}
     end
   end
 
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 92b3254..6e27b68 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,6 +1,7 @@
 require File.expand_path('../../lib/active_pdftk', __FILE__)
 
 require 'rspec'
+require 'digest'
 
 Dir[File.expand_path(File.join(File.dirname(__FILE__),'support','**','*.rb'))].each {|f| require f}
 
@@ -13,4 +14,4 @@
 
   config.filter_run :focus => true
   config.run_all_when_everything_filtered = true
-end
\ No newline at end of file
+end