The iPhone doesn’t have an option to block numbers. Fortunately though, there are a few ways you can make sure that unwanted calls don’t get through. Often times you can simply contact your carrier and request they block the call(s). Sprint allows up to fifty blocked calls and other carriers charge for this service, so make sure and ask before making the request if you don’t want to pay any additional fees.

Another way to block a number on your iPhone is to jailbreak your phone and install a call blocking app. Apps such as Call Bliss, Call Blocker and iBlacklist can be found through Cydia. These apps will allow you to block numbers by sending them straight to your voicemail or setting the ringtone to silent. iBlacklist seems to be the most popular one of these type of apps.

The easiest way to avoid having to deal with unwanted calls is to set the ringtone and vibration setting to “None” for the phone numbers you want to have blocked from your iPhone. To do this, go to your contacts and choose the number you want to edit. While this doesn’t actually block the number from calling, it at least makes it so you don’t have to screen it.

If you’ve upgrade to ios 7, watch the video below for an additional way to block calls:

http://appadvice.com/appnn/2013/10/appadvice-daily-block-annoying-callers-in-ios-7