The effect of liposomal drug encapsulation on the distribution pattern of the encapsulated drug, in tumor and normal tissues of tumor-bearing mouse, was studied. The radioactivity content in some selected organs and serum, after administration of 14C- Labelled misonidazole, was followed at different time intervals. Depending on liposomal the drug formulation type, the uptake of the drug into normal tissue and serum was found to be variable and could be arranged in the following descending order drug fee form > Small unilamellar liposomally encapsulated drug > multilamellar liposomally encapsulated drug On the contrary, the uptake of the drug into tumor tissues was greatest for multilamellar liposomal form, less for small unilamellar liposomes and least for drug fee form. Also, the half-time (t_1/2) for drug clearance was longest for multilamellar liposome, less for small unilamellar liposome and least for drug free form .However, for both liposomal types, the half-time for drug clearance was longest for positively charged liposomes and least for negatively charged type. It could be concluded that multilamellar liposomes with positive surface charge represented an optimal or most suitable formnulation for modulatıng drug action in cancer therapy and targeting the drug to the selected site of action.