Heptaplatin, cis-Malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolane]platinum(II), is a novel platinum-based antitumor agent with clinical potential against human stomach cancer and the 3rd generation of the cisplatin. This study was performed to study how cisplain, heptaplatin and sunpla which is a mixture of heptaplatin and mannitol (w: w=l : 2) affect cell viability of SK-MEL-28 human melanoma cell line. Heptaplatin ($IC_{50}$/; 95.35 $mu$M) and sunpla ($IC_{50}$/; 10.95 11M) were less effect than cisplatin (IC $_{50}$; 10.92 $mu$M) on the SK-MEL-28 cells. By cell cycle analysis using flow cytometry, it was identified that the cells were arrested at G2/M phase by cisplatin, heptaplatin and sunpla, and percentage of cell death group was increased according to increasing of time and concentration. These results suggest that cisplatin, heptaplatin and sunpla are a novel anticancer agent against human melanoma cell.l.