This book constitutes the refereed proceedings of the 4th International Workshop on Biomedical Image Registration, WBIR 2010, held in L?beck, Germany, in July 2010. The 17 revised full papers and 7 revised poster papers presented were carefully reviewed and selected for inclusion in the book. The papers cover all areas of biomedical image registration and are organized in topical sections on biomedical applications, evaluation, methods of registration, and model based registration.