The hydrolysis processes of cytotoxic Pt(II) and Pd(II) complexes bearing benzimidazole moieties were explored combining density functional theory with conductor-like polarisable continuum model (CPCM) approach. Pentacoordinated transition state (TS) structures as well as the other stationary points for two distinct paths were optimized and characterized. The computed potential energy surfaces reveal the rate-limiting step as the second aquation, suggesting that the monohydrated complex is most likely to react with the DNA bases. The results give detailed energy profiles for the hydrolysis mechanism, which may assist in understanding the interaction of such anticancer agents with their ultimate cellular target. (C) 2017 Elsevier B.V. All rights reserved.