diff --git a/nvm.sh b/nvm.sh
index a782441..4509dc7 100644
--- a/nvm.sh
+++ b/nvm.sh
@@ -153,12 +153,16 @@ nvm_ls() {
     return
   fi
   # If it looks like an explicit version, don't do anything funny
-  if [ `expr "$PATTERN" : "v[[:digit:]]*\.[[:digit:]]*\.[[:digit:]]*$"` != 0 ]; then
+  if [ `expr "$PATTERN" : "v[0-9]*\.[0-9]*\.[0-9]*$"` != 0 ]; then
     if [ -d "$NVM_DIR/$PATTERN" ]; then
       VERSIONS="$PATTERN"
     fi
   else
-    VERSIONS=`find "$NVM_DIR/" -maxdepth 1 -type d -name "$(nvm_format_version $PATTERN)*" -exec basename '{}' ';' \
+    PATTERN=$(nvm_format_version $PATTERN)
+    if [ `expr "$PATTERN" : "v[0-9]*\.[0-9]*$"` != 0 ]; then
+      PATTERN="$PATTERN."
+    fi
+    VERSIONS=`find "$NVM_DIR/" -maxdepth 1 -type d -name "$PATTERN*" -exec basename '{}' ';' \
       | sort -t. -u -k 1.2,1n -k 2,2n -k 3,3n | \grep -v '^ *\.'`
   fi
   if [ -z "$VERSIONS" ]; then
diff --git "a/test/fast/Listing versions/Running \"nvm ls 0.2\" should display only 0.2.x versions." "b/test/fast/Listing versions/Running \"nvm ls 0.2\" should display only 0.2.x versions."
index dda41ba..8889f09 100755
--- "a/test/fast/Listing versions/Running \"nvm ls 0.2\" should display only 0.2.x versions."	
+++ "b/test/fast/Listing versions/Running \"nvm ls 0.2\" should display only 0.2.x versions."	
@@ -2,11 +2,40 @@
 
 mkdir ../../../v0.1.3
 mkdir ../../../v0.2.3
+mkdir ../../../v0.20.3
 
 . ../../../nvm.sh
 
+die () { echo $@ ; exit 1; }
+
 # The result should contain only the appropriate version numbers.
-nvm ls 0.2 | grep v0.2.3 &&
-nvm ls 0.1 | grep -v v0.2.3 &&
-nvm ls 0.1 | grep v0.1.3 &&
-nvm ls v0.2 | grep v0.2.3
+
+nvm ls 0.1 | grep 'v0.2.3' > /dev/null
+if [ $? -eq 0 ]; then
+  echo '"nvm ls 0.1" contained v0.2.3'
+fi
+
+nvm ls 0.1 | grep 'v0.20.3' > /dev/null
+if [ $? -eq 0 ]; then
+  die '"nvm ls 0.1" contained v0.20.3'
+fi
+
+nvm ls 0.1 | grep 'v0.1.3' > /dev/null
+if [ $? -ne 0  ]; then
+  die '"nvm ls 0.1" did not contain v0.1.3'
+fi
+
+nvm ls 0.2 | grep 'v0.2.3' > /dev/null
+if [ $? -ne 0  ]; then
+  die '"nvm ls 0.2" did not contain v0.2.3'
+fi
+
+nvm ls 0.2 | grep 'v0.20.3' > /dev/null
+if [ $? -eq 0  ]; then
+  die '"nvm ls 0.2" contained v0.20.3'
+fi
+
+nvm ls 0.2 | grep 'v0.2.3' > /dev/null
+if [ $? -ne 0  ]; then
+  die '"nvm ls 0.2" did not contain v0.2.3'
+fi