A mitomycin C (MMC)-soybean phosphatidyhlcholine complex loaded in phytosomes was previously reported for the purpose of developing a MMC drug delivery system (Mol. Pharmaceutics 2013, 10, 90-101), but this approach was limited by rapid elimination from the body and lack of target specificity. In this article, to overcome these limitations, MMC-soybean phosphatidyhlcholine complex-loaded phytosomes (MMC-loaded phytosomes) as drug carriers were surface-functionalized with folate-PEG (FA-PEG) to achieve reduced toxicity and a superior MMC-mediated therapeutic effect. For this purpose, FA was conjugated to DSPE-PEG-NH2, and the resultant DSPE-PEG-FA was introduced into the lipid moiety of the phytosomes via a postinsertion technique. The prepared FA-PEG-functionalized MMC-loaded phytosomes (FA-PEG-MMC-loaded phytosomes) have a particle size of 201.9 ± 2.4 nm, a PDI of 0.143 ± 0.010, a zeta potential of -27.50 ± 1.67 mV, a spherical shape, and sustained drug release. The remarkable features of FA-PEG-MMC-loaded phytosomes included increased cellular uptake in HeLa cells and higher accumulation in H22 tumor-bearing mice over that of the PEG-MMC-loaded phytosomes. Furthermore, FA-PEG-MMC-loaded phytosomes were associated with enhanced cytotoxic activity in vitro and an improved antitumor effect in vivo compared to that resulting from free MMC injection. These results suggest that FA-PEG-MMC-loaded phytosomes may be useful drug delivery systems for widening the therapeutic window of MMC in clinical trials.