A cobalt(II) complex containing mixed-ligands of 1, 10-phenathrolinc (phen) and glycollic acid (GA). [Co(GA)2(phen)] was synthesized and its structure was characterized by X-ray diffraction. The interaction of the complex with DNA was investigated by electronic absorption spectra and electrochemical methods. Electronic absorption spectrum experiments showed that after interaction with DNA, the characteristic absorption peaks of [Co(GA)2(phen)] underwent hypochromic effect as well as red-shift. Also, the binding strength of 3.8 × l04 L/mol was estimated by titration method. Electrochemical assays revealed that the redox peak currents of the complex decreased obviously accompanied by a positive shift of the formal potential after association with DNA. All these results revealed that the synthesized cobalt complex bound with DNA via an intercalation mode. ? 2011 Wen Qi Li. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.