There has been considerable interest in the development of direct methanol fuel cells (DMFCs) for portable applications. During the last fifteen years, U. S. Army and Defense Advanced Research Project Agency (DARPA) have supported numerous DMFC research and development projects. At this time, the Army is still supporting many DMFC projects. Recently, a 20W DMFC system is successfully developed and evaluated at the Army Research Laboratory (ARL). The performance of the 20W DMFC system is very good under different environmental conditions. This presentation focuses on the technical challenges confronting a DMFC power system: electrocatalysts, membrane electrolyte, fuel-cell stack, and system issues.