In this study we investigated in vitro and in vivo xenograft growth inhibition by crocin isolated from Kashmiri saffron (Crocus sativus). It was found that crocin decreased cell viability in DLA cells, in a concentration- and time-dependent manner. Significant increase in the lifespan of Dalton's lymphoma bearing animals was noted by 37% and 44%, respectively. Furthermore, animals given treatment before induction of cancer showed 58% increase in lifespan and there was 95.6% reduction of solid tumor in crocin treated animals on the 31st day after tumor inoculation. Crocin also showed significant impact on hematological parameters, like the hemoglobin count and numbers of lymphocytes. These findings support the conclusion that crocin from Crocus sativus has significant anti-tumor activity.