Human serum albumin (HSA)-coated liposomal formulations were synthesized and evaluated for the delivery of antisense oligodeoxyribonucleotide (ODN) G3139 in KB human oral carcinoma cells. Liposomes composed of dimethyldioctadecyl ammonium bromide/egg phosphatidylcholine/α-tocopheryl polyethylene glycol 1000 succinate (58:40:2 molar ratio) complexed with G3139 and coated with HSA were investigated for Bcl-2 downregulating activity. Cellular uptake of HSA-coated liposome−ODN complexes was more efficient than the uncoated liposome−ODN complexes. Treatment of the cells with HSA-coated liposome−ODN complexes resulted in efficient Bcl-2 mRNA downregulation that was approximately 3-fold greater than with uncoated liposomes (p < 0.05) and 6-fold greater than with free ODN. The transfection efficiency of liposome−ODN complexes coated with HSA was dependent on the concentration of HSA used and on the contents of α-helix and β-strand in HSA. HSA-coated liposomes are effective delivery vehicles for antisense ODN.