Objective: Saffron (Crocus sativus) showed anti-cancer activities. However, limited effort has been made to correlate these effects to the active ingredients of saffron. In the present study, cytotoxic effects of crocin, the major coloring compound in saffron, and its nanoliposomal form for better cellular delivery, were investigated. Materials and Methods: HeLa and MCF-7 cells were cultured and exposed to crocin (1, 2 and 4 mM/L) and liposomal crocin (0.5, 1 mM/L). MTT assay was performed to assess cytotoxicity. PI staining of DNA fragments and flow cytometry were used to determination apoptotic cells. Results: By MTT assay a remarkable cytotoxic effect of crocin on HeLa and MCF-7 cells was revealed in comparison to non-malignant cell line (L929). Crocin liposomal forms (IC50s after 48 hours: 0.61 and 1.2 mM/L) showed more cytotoxic effect compared to the crocin (IC50 after 48 hours: 1.603 mM/L). Crocin and its liposomal form induced a sub-G1 peak in flow cytometry histogram of treated cells indicating apoptosis is involved in this toxicity. Liposomal encapsulation enhances apoptogenic effects of crocin on cancerous cells. Conclusion: It might be concluded that crocin and its liposomes could cause cell death in HeLa and MCF-7 cells, in which liposomal encapsulation improved cytotoxic effects. They could be also considered as a promising chemotherapeutic agent in cancer treatment in future.