Caffeine, a methyl xanthine derivative, was studied to assess the effect on B16F10 melanoma induced experimental metastasis. Caffeine was administered at a dose of 100 and 50 mg/kg body weight by both routes, to tumour bearing animals. Solid tumour reduction studies with Caffeine showed a significant reduction in tumour volume for 100 mg/kg dose by both oral and i.p. routes. The Caffeine treated metastatic tumour bearing animals significantly (p<0.001) inhibited lung tumour nodules. Serum sialic acid levels and lung hydroxyproline contents in the treated groups were significantly (p<0.001) low, when compared with the untreated control animals. In the present study, our results suggest that Caffeine inhibits solid tumour development and pulmonary experimental metastasis induced by B16F10 melanoma cells, in murine model.