If you are entering the United States by air or sea carrier you will no longer be required to complete the paper I-94 or I-94W.
The office of the Customs and Border Protection (CBP) will gather your arrival/departure information automatically from your electronic travel records. Because advance information is only transmitted for air and sea travelers, CBP will still issue a paper form I-94 to those entering the United States by land.
Upon arrival in the United States, a CBP officer will stamp your passport with the admission date, the class of admission, and the date that you are admitted until. Upon exiting the United States CBP will record your departure electronically via manifest information provided by the air or sea carrier. For those of you who entered by land, you will surrender the I-94/I94w on your departure.
Your I-94 arrival/departure record and arrival/departure history is available online at https://i94.cbp.dhs.gov/I94/request.html. You can retrieve your I-94 arrival/departure record number and five-year travel history by entering your name, date of birth, and passport information.
If you were issued a paper I-94/I-94W and forgot to hand it in on your departure, click here to be taken to the CBP website for further information and assistance.
If you have lost a paper form I-94 that was issued prior to the online system and the record is not available online, you can file a Form I-102, Application for Replacement/Initial Non-Immigrant Arrival-Departure Document, with U.S. Citizenship and Immigration Services.
(Photo: ##http://www.flickr.com/photos/bartelomeus/189615163/sizes/m/in/photostream/## Bart Van De Bizen on flickr)