diff --git a/src/ua-parser.js b/src/ua-parser.js
index fc3df6e..0885ab2 100755
--- a/src/ua-parser.js
+++ b/src/ua-parser.js
@@ -701,7 +701,7 @@
             /cfnetwork\/.+darwin/i
             ], [[VERSION, /_/g, '.'], [NAME, 'iOS']], [
             /(mac os x)\s?([\w\s\.]*)/i,
-            /(macintosh|mac(?=_powerpc) )(?!.+haiku)/i                          // Mac OS
+            /(macintosh|mac_powerpc\b)(?!.+haiku)/i                         // Mac OS
             ], [[NAME, 'Mac OS'], [VERSION, /_/g, '.']], [
 
             // Mobile OSes                                                      // Android/WebOS/Palm/QNX/Bada/RIM/Maemo/MeeGo/Contiki/Sailfish OS
diff --git a/test/os-test.json b/test/os-test.json
index 3b80025..be59b19 100644
--- a/test/os-test.json
+++ b/test/os-test.json
@@ -728,6 +728,15 @@
             "version" : "undefined"
         }
     },
+    {
+        "desc"    : "Mac OS on PowerPC",
+        "ua"      : "Mozilla/4.0 (compatible; MSIE 5.0b1; Mac_PowerPC)",
+        "expect"  :
+        {
+            "name"    : "Mac OS",
+            "version" : "undefined"
+        }
+    },
     {
         "desc"    : "Mac OS X on x86, x86_64, or aarch64 using Firefox",
         "ua"      : "Mozilla/5.0 (Macintosh; Intel Mac OS X x.y; rv:10.0) Gecko/20100101 Firefox/10.0",