diff --git a/lib/contentstack.js b/lib/contentstack.js
index 4349e23f..09e393bc 100644
--- a/lib/contentstack.js
+++ b/lib/contentstack.js
@@ -182,7 +182,7 @@ export function client (params = {}) {
   let defaultHostName
 
   if (params.region) {
-    const region = params.region.toLowerCase()
+    const region = params.region.toUpperCase()
     if (!regionHostMap[region]) {
       throw new Error(`Invalid region '${params.region}' provided. Allowed regions are: ${Object.keys(regionHostMap).join(', ')}`)
     }