Lost all contact information on my iphone, how do I get it back?

If you synced your phone with iTunes on your Mac, check iTunes/Settings/Devices and see if there is a recent backup of your phone listed. If yes, use it to restore from, contacts are part of the backup.

Also check if syncing contacts is selected in the Info pane in iTunes with your phone connected.

If it says that your contacts can be or are synced from your address book on your Mac, and your address book does have your contacts listed, your contacts will be synced again to your phone the next time you sync it.

Just make sure to have at least one contact listed on the phone, syncing to an iPhone without contacts listed will erase the info on your computer as well.

Contacts

To sync contacts with your computer, choose "Sync Contacts with" within iTunes for Windows, or "Sync Contacts" in OS X v10.8, or "Sync Address Book Contacts" in OS X v10.7 and earlier.

You can sync your contacts with:

• Microsoft Outlook 2003, Microsoft Outlook 2007, Microsoft Outlook 2010 (Windows XP, Windows Vista, Windows 7, and Windows 8)
• Windows Address Book (Windows XP)
• Windows Contacts (Windows Vista, Windows 7, and Windows 8)
• Address Book (Mac OS X v10.7 and earlier)
• Contacts (Mac OS X v10.8)
• Microsoft Entourage 2004, Microsoft Entourage 2008, or Microsoft Outlook 2011 for Mac

Notes:

• When syncing contacts, you can choose to sync all of your contacts or only selected groups. The option to sync selected items may not show up until after the first sync.
• You can select a group of contacts to which all new contacts created on your iOS device will be added.
• Additional options for syncing include syncing your contacts with Yahoo or Gmail/Google Mail. You will need to configure it with the user name and password for your Yahoo or Google account.

copied from iOS: How to transfer or sync content to your computer

First, you could try resetting your phone: Hold down the home button along with the sleep/wake button until you see the apple, then let go. If Contacts still do not show, go into the Contacts app and tap Groups at top left. Make sure all contacts groups are checked.

Similar problem here; hoping someone else will comment with another possible fix. I had trouble earlier today sending texts (could receive just fine). I powered the phone off, waited aobut 15 minutes and then turned it back on. I still can't send texts and now ALL my contacts are gone. 10 years of personal and profession info seems to be lost--and I have no idea how long ago it was when I last synced with my Mac since I normally recharge through the regular power outlet/adapter.

@CGmommie74

Check iTunes/Settings/Devices to see all backups made by iTunes on your computer.

If you set up iCloud to do the backups, your device will backup as soon it enters standby and has a Wi-Fi connection.

See also:

iOS: About backups

backups in iCloud

Thanks, @Ingo2711. Sadly, I have been lax in backing up to iTunes; it's been over a year (I thought to check right after I posted). I am seeing a lot of posts from people having similar issues and a few saying their contacts came back after a couple resets, so I'm not giving up hope yet. Although I am tracking down all the paper address books I can find...

Glad you got your contacts working again, seems syncing contacts with your computer and iCloud does not go well together.😉

Did you already reset the phone by holding the sleep and home button for about 10sec, until the Apple logo comes back again? This could help with the freezing iMessage app. You will not lose data by resetting, but it can cure some glitches after installing new software or apps.

no backup is also ok for recovering your contacts, you can manage it with a free iphone data recovery.and it is very easy to use,and cost no money. waiting for your good news~😝

haha, very good~

Here's a screenshot from Turn your iOS device off and on (restart) and reset

All buttons are also mentioned on page 8 of the iPhone user guide