Recent advances in the search for novel anticanceragents have indicated that the positively chargedantimicrobial peptides have emerged as promising agentsoffering several advantages over the conventional anticancerdrugs. As a naturally occurring, cationic, a-helicalantimicrobial peptide, temproin-1CEa has been proved toexhibit a potent anticancer effect and a moderate hemolyticactivity. In order to reduce the hemolytic activity of temporin-1CEa and improve its anticancer potency towards arange of human breast cancer cells, in the present study, sixanalogs of temporin-1CEa were rationally designed andsynthesized. The amphipathicity levels and a-helicalstructural patterns of peptides were reserved, while theircationic property and hydrophobicity were changed. Theresults of MTT and hemolysis assay indicated that theanalog peptides displayed an improved anticancer activityand showed an overall optimized therapeutic index. Thehydrophobicity of peptides was positively correlated withtheir hemolytic and antitumor activities. Moreover, the datasuggest a strategy of increasing the cationicity whilemaintaining the moderate hydrophobicity of naturallyoccurring amphipathic a-helical peptides to generate analogswith improved cytotoxicity against tumor cells butdecreased activity against non-neoplastic cells such ashuman erythrocytes. This work highlights the potential forrational design and synthesis of improved antimicrobialpeptides that have the capability to be used therapeuticallyfor treatment of cancers.