diff --git a/package.json b/package.json
index e8eb273..7c4fbfd 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "ussd-tg-proxy",
-  "version": "0.2.6",
+  "version": "0.3.0",
   "description": "ussd-tg-proxy",
   "main": "src/index.js",
   "repository": "https://git.grassecon.net/grassrootseconomics/ussd-tg-proxy.git",
diff --git a/src/bot.js b/src/bot.js
index f5f2402..e6b4176 100644
--- a/src/bot.js
+++ b/src/bot.js
@@ -77,8 +77,11 @@ bot.on("msg:contact", async (ctx) => {
   log.debug(ctx.update, "msg:contact received");
   const contact = ctx.msg.contact;
 
-  if (ctx.from.id === contact.user_id) {
-    await cache.set(contact.user_id, contact.phone_number.slice(1));
+  if (
+    ctx.from.id === contact.user_id &&
+    util.isKenyanNumber(contact.phone_number)
+  ) {
+    await cache.set(contact.user_id, contact.phone_number);
 
     return ctx.reply(
       "Phone number successfully linked. /start the bot again to access your Sarafu account."
diff --git a/src/util.js b/src/util.js
index a6d2a20..15f3f1e 100644
--- a/src/util.js
+++ b/src/util.js
@@ -15,7 +15,20 @@ function parseUssdResponse(input) {
   };
 }
 
+function isKenyanNumber(input) {
+  if (input.substr(0, 1) === "+") {
+    input = input.split("+")[1];
+  }
+
+  if (input.substr(0, 3) === "254") {
+    return true;
+  }
+
+  return false;
+}
+
 module.exports = {
   createKeyboard,
   parseUssdResponse,
+  isKenyanNumber,
 };
diff --git a/tests/util.test.js b/tests/util.test.js
index 1b5ce72..780a092 100644
--- a/tests/util.test.js
+++ b/tests/util.test.js
@@ -3,7 +3,7 @@ const test = require("tap").test;
 const util = require("../src/util");
 
 test("util", (t) => {
-  t.plan(4);
+  t.plan(8);
 
   t.test("keyboard from single digit reply options", (t) => {
     const rawText = `CON Balance 80.0 GFT
@@ -66,4 +66,32 @@ test("util", (t) => {
     t.same(output, expect);
     t.end();
   });
+
+  t.test("kenyan number formatted", (t) => {
+    const number = "+254700123456";
+
+    t.equal(util.isKenyanNumber(number), true);
+    t.end();
+  });
+
+  t.test("kenyan number unformatted", (t) => {
+    const number = "254700123456";
+
+    t.equal(util.isKenyanNumber(number), true);
+    t.end();
+  });
+
+  t.test("non kenyan number formatted", (t) => {
+    const number = "+441632960198";
+
+    t.equal(util.isKenyanNumber(number), false);
+    t.end();
+  });
+
+  t.test("non kenyan number unformatted", (t) => {
+    const number = "12029182132";
+
+    t.equal(util.isKenyanNumber(number), false);
+    t.end();
+  });
 });