diff --git a/src/rosdep2/installers.py b/src/rosdep2/installers.py
index 27cdb207c..5d3049767 100644
--- a/src/rosdep2/installers.py
+++ b/src/rosdep2/installers.py
@@ -398,6 +398,18 @@ def get_depends(self, rosdep_args):
             return rosdep_args.get('depends', [])
         return [] # Default return empty list
 
+
+def normalize_uninstalled_to_list(uninstalled):
+    uninstalled_dependencies = []
+    for pkg_or_list in [v for k, v in uninstalled]:
+        if isinstance(pkg_or_list, list):
+            for pkg in pkg_or_list:
+                uninstalled_dependencies.append(str(pkg))
+        else:
+            uninstalled_dependencies.append(str(pkg))
+    return uninstalled_dependencies
+
+
 class RosdepInstaller(object):
 
     def __init__(self, installer_context, lookup):
@@ -484,8 +496,12 @@ def install(self, uninstalled, interactive=True, simulate=False,
             installer.install(uninstalled)
         """
         if verbose:
-            print("install options: reinstall[%s] simulate[%s] interactive[%s]"%(reinstall, simulate, interactive))
-            print("install: uninstalled keys are %s"%(', '.join([', '.join(pkg) for pkg in [v for k,v in uninstalled]])))
+            print(
+                "install options: reinstall[%s] simulate[%s] interactive[%s]" %
+                (reinstall, simulate, interactive)
+            )
+            uninstalled_list = normalize_uninstalled_to_list(uninstalled)
+            print("install: uninstalled keys are %s" % ', '.join(uninstalled_list))
 
         # Squash uninstalled again, in case some dependencies were already installed
         squashed_uninstalled = []
diff --git a/src/rosdep2/main.py b/src/rosdep2/main.py
index 90b55a803..b3e4a3da1 100644
--- a/src/rosdep2/main.py
+++ b/src/rosdep2/main.py
@@ -60,6 +60,7 @@
 from . import create_default_installer_context, get_default_installer
 from . import __version__
 from .core import RosdepInternalError, InstallFailed, UnsupportedOs, InvalidData, CachePermissionError
+from .installers import normalize_uninstalled_to_list
 from .installers import RosdepInstaller
 from .lookup import RosdepLookup, ResolutionError
 from .rospkg_loader import DEFAULT_VIEW_KEY
@@ -660,7 +661,8 @@ def command_install(lookup, packages, options):
         uninstalled, errors = installer.get_uninstalled(packages, implicit=options.recursive, verbose=options.verbose)
 
     if options.verbose:
-        print("uninstalled dependencies are: [%s]"%(', '.join([', '.join(pkg) for pkg in [v for k,v in uninstalled]])))
+        uninstalled_dependencies = normalize_uninstalled_to_list(uninstalled)
+        print("uninstalled dependencies are: [%s]" % ', '.join(uninstalled_dependencies))
 
     if errors:
         err_msg = ("ERROR: the following packages/stacks could not have their "