Where can I buy missing LEGO pieces?

LEGO's customer service website allows customers to order LEGO pieces that are missing from new LEGO sets or purchase a replacement part for a set they currently own. Customers will need to have the set number or be able to describe the set.

Once the request for a missing piece has been submitted and processed, the piece will be mailed directly to the customer. For customers who have lost a LEGO piece and want a replacement, the company recommends using their Pick a Brick service. This service lets customers browse LEGO's large number of pieces and purchase them individually. The site also recommends Pick a Brick for customers who are trying to find replacement pieces for older LEGO sets.