The Circo child booster seat was sold at Target stores nationwide until June of 2009 when it was first recalled.
The seat's restraint buckle can open unexpectedly allowing a child to fall from the chair and be injured.
The initial recall involved about 43,000 seats. That has grown to 375,000 seats.
Consumers should immediately stop using the recalled booster seats and return them to any Target store for a full refund.
For additional information, contact Target at (800) 440-0680 between 7 a.m. and 6 p.m. CT Monday through Friday, or visit the firm's website at www.target.com