Abstract: Cis-dichloro-trans-dihydroxy-bis-isopropylamine platinum (Ⅳ) (CHIP), a second-generation platinum compound, is known to have high antitumor activity and low renal toxicity. The effects of CHIP on the cytokinetics of Ehrlich ascite carcinoma (EAC) growing in mice were studied by means of autoradiography, Stathmokinetic and microcytometry methods. After an i. p. dose of 30 mg/kg, CHIP was shown to inhibit the proliferation of either the cells in exponentially growing phase or the cells on plateau phase. The G₀ cells may also be damaged while no specific killing effect was found for the cells in the S or M phase. CHIP induced extensive delay of the progression through the whole cell cycle of EAC, especially the progression from G₁ to S phase. The findings suggest that CHIP may be classified as a cell cycle non-specific agent.