We synthesized specific nano-porous dendritic structures similar to cedar leaves of manganese oxides using pulsed laser ablation (PLA) process, with the potential for use as highly active nano-catalysts. The nano-porous structures were formed by self-assembled agglomeration of nanocrystallites without templates. Furthermore, the dendritic nano-porous manganese oxide as an electrocatalyst showed a significant decrease in overpotential on oxygen reduction in alkaline electrolyte. (c) 2005 Elsevier B.V. All rights reserved.