diff --git a/lib/mongo/util/uri_parser.rb b/lib/mongo/util/uri_parser.rb
index b2af56f..51a1602 100644
--- a/lib/mongo/util/uri_parser.rb
+++ b/lib/mongo/util/uri_parser.rb
@@ -20,8 +20,20 @@ module Mongo
   class URIParser
 
     DEFAULT_PORT = 27017
-    MONGODB_URI_MATCHER = /(([-.\w:]+):([^@,]+)@)?((?:(?:[-.\w]+)(?::(?:[\w]+))?,?)+)(\/([-\w]+))?/
+
+    USER_REGEX = /(?<username>[-.\w:]+)/
+    PASS_REGEX = /(?<password>[^@,]+)/
+    AUTH_REGEX = /(?<auth>#{USER_REGEX}:#{PASS_REGEX}@)?/
+
+    HOST_REGEX = /(?<host>[-.\w]+)/
+    PORT_REGEX = /(?::(?<port>\w+))?/
+    NODE_REGEX = /(?<nodes>(#{HOST_REGEX}#{PORT_REGEX},?)+)/
+
+    PATH_REGEX = /(?:\/(?<path>[-\w]+))?/
+
+    MONGODB_URI_MATCHER = /#{AUTH_REGEX}#{NODE_REGEX}#{PATH_REGEX}/
     MONGODB_URI_SPEC = "mongodb://[username:password@]host1[:port1][,host2[:port2],...[,hostN[:portN]]][/database]"
+
     SPEC_ATTRS = [:nodes, :auths]
     OPT_ATTRS  = [:connect, :replicaset, :slaveok, :safe, :w, :wtimeout, :fsync]
 
@@ -118,10 +130,10 @@ module Mongo
         raise MongoArgumentError, "MongoDB URI must match this spec: #{MONGODB_URI_SPEC}"
       end
 
-      uname    = matches[2]
-      pwd      = matches[3]
-      hosturis = matches[4].split(',')
-      db       = matches[6]
+      uname    = matches['username']
+      pwd      = matches['password']
+      hosturis = matches['nodes'].split(',')
+      db       = matches['path']
 
       hosturis.each do |hosturi|
         # If port is present, use it, otherwise use default port