This book constitutes the refereed proceedings of the 4th International Conference on Audio-and Video-Based Biometric Person Authentication, AVBPA 2003, held in Guilford, UK in June 2003.The 39 revised full plenary papers and 72 revised full poster papers were carefully reviewed and selected for presentation. There are topical sections on face; speech; fingerprint; image,video processing, and tracking; general issues; handwriting, signature, and palm; gait; and fusion