Personal Effects: Tourists are allowed to bring in their personal effects duty-free. According to customs regulations, in addition to clothing, personal effects may include one camera, one video cassette player, one personal computer, one CD player, 5 DVDs, 20 music CDs or audiocassettes, 12 rolls of unused film, and one cellular phone. Any tourist carrying such items, even if duty-free, should enter the "Merchandise to Declare" lane at the first customs checkpoint. The tourist should be prepared to pay any assessed duty. Failure to declare personal effects routinely results in the seizure of the goods as contraband.
For more information visit the website for Mexican Customs website