As alternative bipolar plate materials for polymer electrolyte membrane fuel cell (PEMFC), two types of carbon composite were developed and characterized. Electrical and physical properties of the currently used graphite and newly developed carbon composites were evaluated in terms of bulk and contact resistance, flexural strength, density, gas tightness, water absorption, and depth deviation of the flow channel. The test results showed that the carbon composites were very promising candidates for PEMFC bipolar plate material. In single cell tests, the carbon composite bipolar plates exhibited good initial and long-term performance compared with the graphite bipolar plates. (C) 2003 Published by Elsevier B.V.