The structural, optical and electrical properties of cupric oxide (CuO) films coated by DC magnetron sputtering method under different oxygen flow rate (0%, 35%, 70%) were examined. The electrical transport mechanism of the films was also investigated in a temperature range of 110-400 K. Electrical conductivity of the films mainly affected by oxygen flow rate since density of states (DOS) was critically dependent on the oxygen flow rate. Considering oxygen flow rate, a direct link between the DOS and electrical properties of the films was established. (C) 2015 Elsevier B.V. All rights reserved.