diff --git a/tools/roslaunch/src/roslaunch/loader.py b/tools/roslaunch/src/roslaunch/loader.py
index dac9ac413d..8b884b6bd9 100644
--- a/tools/roslaunch/src/roslaunch/loader.py
+++ b/tools/roslaunch/src/roslaunch/loader.py
@@ -39,12 +39,13 @@
 import os
 from copy import deepcopy
 
+import yaml
+
 from roslaunch.core import Param, RosbinExecutable, RLException, PHASE_SETUP
 
 from rosgraph.names import make_global_ns, ns_join, PRIV_NAME, load_mappings, is_legal_name, canonicalize_name
 
 #lazy-import global for yaml and rosparam
-yaml = None
 rosparam = None
 
 class LoadException(RLException):
@@ -88,12 +89,17 @@ def convert_value(value, type_):
     elif type_ == 'double':
         return float(value)
     elif type_ == 'bool' or type_ == 'boolean':
-        value = value.lower()
+        value = value.lower().strip()
         if value == 'true' or value == '1':
             return True
         elif value == 'false' or value == '0':
             return False
         raise ValueError("%s is not a '%s' type"%(value, type_))
+    elif type_ == 'yaml':
+        try:
+            return yaml.load(value)
+        except yaml.parser.ParserError as e:
+            raise ValueError(e)
     else:
         raise ValueError("Unknown type '%s'"%type_)        
 
@@ -395,10 +401,6 @@ def load_rosparam(self, context, ros_config, cmd, param, file_, text, verbose=Tr
                     text = f.read()
                     
             # parse YAML text
-            # - lazy import
-            global yaml
-            if yaml is None:
-                import yaml
             # - lazy import: we have to import rosparam in oder to to configure the YAML constructors
             global rosparam
             if rosparam is None:
@@ -468,7 +470,7 @@ def param_value(self, verbose, name, ptype, value, textfile, binfile, command):
             return convert_value(value.strip(), ptype)
         elif textfile is not None:
             with open(textfile, 'r') as f:
-                return f.read()
+                return convert_value(f.read(), ptype)
         elif binfile is not None:
             try:
                 from xmlrpc.client import Binary
@@ -498,7 +500,7 @@ def param_value(self, verbose, name, ptype, value, textfile, binfile, command):
                 raise
             if c_value is None:
                 raise ValueError("parameter: unable to get output of command [%s]"%command)
-            return c_value
+            return convert_value(c_value, ptype)
         else: #_param_tag prevalidates, so this should not be reachable
             raise ValueError("unable to determine parameter value")
 
diff --git a/tools/roslaunch/test/xml/test-params-valid.xml b/tools/roslaunch/test/xml/test-params-valid.xml
index 428a9b4c88..7ae940c90b 100644
--- a/tools/roslaunch/test/xml/test-params-valid.xml
+++ b/tools/roslaunch/test/xml/test-params-valid.xml
@@ -17,6 +17,9 @@
   
   <param name="somefloat1" value="3.14159" type="double" />  
   <param name="somefloat2" value="5.0" />
+
+  <param name="someyaml1" value="[0, 1, 2]" type="yaml" />
+  <param name="someyaml2" value="{string1: bar2, string2: '10', integer1: 1, float1: 3.14, list1: [0, 1, 2], list2: ['a', 'b', 'c']}" type="yaml" />
   
   <!-- you can set parameters in child namespaces -->
   <param name="wg/wgchildparam" value="a child namespace parameter 1" />  
@@ -32,6 +35,12 @@
   <!-- upload the output of a command as a param. -->
   <param name="commandoutput" command="cat &quot;$(find roslaunch)/resources/example.launch&quot;" />
 
+  <!-- upload the output of a command as a param as types. -->
+  <param name="commandoutputinteger" type="int" command="echo 0" />
+  <param name="commandoutputdouble" type="double" command="echo 10" />
+  <param name="commandoutputbool" type="bool" command="echo true" />
+  <param name="commandoutputyaml" type="yaml" command="cat &quot;$(find roslaunch)/test/params.yaml&quot;" />
+
 
   <!-- test that we can override params -->
   <param name="override" value="fail" />