All high school students who take Advanced Placement (AP) classes can take a corresponding exam for a chance to earn college credit. For identification purposes, you receive an AP number for all your exams the first time you take a test. If you've misplaced your AP number, don't panic. Nothing bad happens, but you do need the number to order additional score reports. There are several easy ways to obtain a lost AP number.

AP Student Pack

Check to see if you still have your AP student pack. All students are supposed to receive one on exam day, and this is the easiest way to find your AP number if you recently took your exams. The AP student pack is an envelope that includes several important items, including instructions for taking the test and receiving score reports. Your AP number should be printed on the front of the booklet.

AP Score Report

Even if you lost your AP number after taking your exams, you still automatically receive a score report in July. Your scores are also sent to your high school and to the colleges and universities you wrote on your answer sheet. Score reports are cumulative, so unless you requested certain scores to be canceled or withheld, all your AP scores are automatically included. Your AP number is listed next to your name.

Call AP Services

If you still can't locate your AP number, the College Board can help. They maintain a comprehensive record for every person who takes an AP exam, which means they can look up your AP number for you. Call AP Services at (609) 771-7300 or toll free (in the United States and Canada) at (888) 225-5427 to request it. Be ready to provide your name, address and Social Security number so they can verify your identity.

Old AP Scores

If you took the AP test more than four years ago, you need to use a different method to obtain your scores. They have been archived, and you can retrieve them without using your AP number. Download the Archived AP Scores Request Form from the College Board's website and send it to the address indicated at the bottom, along with a $25 payment (as of May, 2011) for each report you'd like to receive.