Chitosan and bovine serum albumin were co-patterned onto a glass substrate by microcontact printing technique. The process uses a microfabricated polydimethylsiloxane stamp to transfer chitosan on an aldehyde functionalized glass substrate, followed by adding a drop of albumin solution to the patterned side and holding for 30 min. After being washed with phosphate-buffered saline and cleaned by ultrasonic, the co-patterns of chitosan and albumin, each with their own micropatterns, were formed on the same surface. In this procedure, ultrasonic cleaning takes an important role to obtain clear patterns, whereas the printing/adding sequence has less influence. Moreover, patterns printed could give higher contrast than those assembled from solution. These co-patterns could find applications in cell localization and cell growth guidance. (C) 2004 Elsevier B.V. All rights reserved.