Check first with the front desk or lost and found at the destination where you were dropped off; the driver may have returned your item there.
Call or stop by the police lost and found center closest to your final destination. Each borough of New York City has its own lost and found center, which can be located on the New York City Taxi & Limousine Commission website.
Gather information about your taxi ride and the lost property if you are unable to find it at the police station. Check your receipt and write down the taxi's medallion number (a four number/letter combination printed on the receipt), the time and date of your cab ride, pick up and drop-off locations, how you paid for your cab ride and the driver's name and/or license plate, if you have this information. Also determine the estimated value of your lost property.
Visit the New York City Taxi and Limousine Commission website to submit a lost property inquiry. Fill out the form on the website; there are different forms depending on if you know the medallion number. Submit the information you gathered about your cab ride in the form, including your contact information.
Call the taxi's garage directly to try and track down your lost property. The Taxi & Limousine Commission will contact you, a few days after you fill out the online form with the information regarding your cab trip, with the taxi's garage number (if they are able to find it).