Acetyl salicylic acid, commonly known as Aspirin or Ecotrin, has been synthesized by an eco-friendly route using solid acid catalysts namely nano-crystalline sulfated zirconia, Sulfated titania, zeolite H-beta, H-Y, H-ZSM-5 and acid treated K-10 clay. Among all the solid acid catalysts studied, nano-crystalline Sulfated zirconia showed highest catalytic activity and Was found to be efficient in minimal amount to obtain excellent yield (95 wt%) of acetyl salicylic acid crystals. Thermally regenerated catalyst showed similar yield as obtained with the fresh catalyst. (C) 2009 Elsevier B.V. All rights reserved.