It may happen that when you want to send a message to one of your WhatsApp contacts, it will not appear in your contact list. This can cause annoyance, especially if you need to send an urgent message. To solve this problem, you just have to follow some simple instructions.
What To Do if Some Contacts do not Show up in WhatsApp
If the friend you are looking for does not appear in WhatsApp's contact list, make sure you have their number registered to your device's contact list, as you may have mistakenly deleted it. Also check that your friend has the app installed and has it updated (you can update it from Google Play). Also check that all your contacts (from your SIM card, Google and the internal memory of your device) and contact groups (like friends and family) appear in the contacts list on your Android device. To show all your contacts, go to the Contacts tab, press Menu and select Settings. Then uncheck Show All and re-check this option:
Go to the Contacts tab, press Menu and select Refresh:
Your friend should now appear in your contact list WhatsApp.