AbstractLiposomes as drug carriers in cancer chemotherapy have attracted considerable interest. To enhance the therapeutic effect of Adriamycin entrapped in liposomes (Lip‐ADM) on human solid tumors, we investigated the therapeutic effects of Lip‐ADM in combination with recombinant human tumor necrosis factor‐α (rTNF‐α), which is known to have specific effects on tumor vasculature. rTNF‐α or saline solution was injected intravenously into nude mice bearing a human colon cancer strain, HC‐1, at 1 hour before intravenous administration of Lip‐ADM. The significant therapeutic effect of Lip‐ADM in combination with rTNF‐α was demonstrated by the evaluation with tumor growth curve and the actual tumor weights, in comparison with groups of mice treated with saline solution, rTNF‐α alone, or with a Lip‐ADM after saline. Levels of Adriamycin in tumor tissue in the Lip‐ADM in combination with rTNF‐α‐treated group were higher than those in Lip‐ADM