diff --git a/src/Composer/Package/Version/VersionParser.php b/src/Composer/Package/Version/VersionParser.php
index ff60c3d0d..8d0d4d0f2 100644
--- a/src/Composer/Package/Version/VersionParser.php
+++ b/src/Composer/Package/Version/VersionParser.php
@@ -128,10 +128,7 @@ class VersionParser
                 if ('stable' === $matches[$index]) {
                     return $version;
                 }
-                $mod = array('{^pl?$}i', '{^rc$}i');
-                $modNormalized = array('patch', 'RC');
-                $version .= '-'.preg_replace($mod, $modNormalized, strtolower($matches[$index]))
-                    . (!empty($matches[$index+1]) ? $matches[$index+1] : '');
+                $version .= '-' . $this->expandStability($matches[$index]) . (!empty($matches[$index+1]) ? $matches[$index+1] : '');
             }
 
             if (!empty($matches[$index+2])) {
@@ -259,22 +256,30 @@ class VersionParser
             return array();
         }
 
-        if (preg_match('{^~(\d+)(?:\.(\d+))?(?:\.(\d+))?(?:\.(\d+))?$}', $constraint, $matches)) {
-            if (isset($matches[4])) {
+        if (preg_match('{^~(\d+)(?:\.(\d+))?(?:\.(\d+))?(?:\.(\d+))?'.self::$modifierRegex.'?$}', $constraint, $matches)) {
+            if (isset($matches[4]) && '' !== $matches[4]) {
                 $highVersion = $matches[1] . '.' . $matches[2] . '.' . ($matches[3] + 1) . '.0-dev';
                 $lowVersion = $matches[1] . '.' . $matches[2] . '.' . $matches[3]. '.' . $matches[4];
-            } elseif (isset($matches[3])) {
+            } elseif (isset($matches[3]) && '' !== $matches[3]) {
                 $highVersion = $matches[1] . '.' . ($matches[2] + 1) . '.0.0-dev';
                 $lowVersion = $matches[1] . '.' . $matches[2] . '.' . $matches[3]. '.0';
             } else {
                 $highVersion = ($matches[1] + 1) . '.0.0.0-dev';
-                if (isset($matches[2])) {
+                if (isset($matches[2]) && '' !== $matches[2]) {
                     $lowVersion = $matches[1] . '.' . $matches[2] . '.0.0';
                 } else {
                     $lowVersion = $matches[1] . '.0.0.0';
                 }
             }
 
+            if (!empty($matches[5])) {
+                $lowVersion .= '-' . $this->expandStability($matches[5]) . (!empty($matches[6]) ? $matches[6] : '');
+            }
+
+            if (!empty($matches[7])) {
+                $lowVersion .= '-dev';
+            }
+
             return array(
                 new VersionConstraint('>=', $lowVersion),
                 new VersionConstraint('<', $highVersion),
@@ -337,6 +342,25 @@ class VersionParser
         throw new \UnexpectedValueException($message);
     }
 
+    private function expandStability($stability)
+    {
+        $stability = strtolower($stability);
+
+        switch ($stability) {
+            case 'a':
+                return 'alpha';
+            case 'b':
+                return 'beta';
+            case 'p':
+            case 'pl':
+                return 'patch';
+            case 'rc':
+                return 'RC';
+            default:
+                return $stability;
+        }
+    }
+
     /**
      * Parses a name/version pairs and returns an array of pairs + the
      *
diff --git a/tests/Composer/Test/Package/Version/VersionParserTest.php b/tests/Composer/Test/Package/Version/VersionParserTest.php
index 99a4237da..c115a4e22 100644
--- a/tests/Composer/Test/Package/Version/VersionParserTest.php
+++ b/tests/Composer/Test/Package/Version/VersionParserTest.php
@@ -263,6 +263,9 @@ class VersionParserTest extends \PHPUnit_Framework_TestCase
             array('~1.2',     new VersionConstraint('>=', '1.2.0.0'), new VersionConstraint('<', '2.0.0.0-dev')),
             array('~1.2.3',   new VersionConstraint('>=', '1.2.3.0'), new VersionConstraint('<', '1.3.0.0-dev')),
             array('~1.2.3.4', new VersionConstraint('>=', '1.2.3.4'), new VersionConstraint('<', '1.2.4.0-dev')),
+            array('~1.2-beta',new VersionConstraint('>=', '1.2.0.0-beta'), new VersionConstraint('<', '2.0.0.0-dev')),
+            array('~1.2-b2',  new VersionConstraint('>=', '1.2.0.0-beta2'), new VersionConstraint('<', '2.0.0.0-dev')),
+            array('~1.2.2-dev', new VersionConstraint('>=', '1.2.2.0-dev'), new VersionConstraint('<', '1.3.0.0-dev')),
         );
     }