The current study developed a psychometrically sound multidimensional measure of Internet addiction: the Chinese Internet Addiction Inventory (CIAI). Data were collected from 1,029 Chinese undergraduate students from 14 universities and colleges. The initial sample was split randomly into two samples (N1 = 516; N2 = 513). An exploratory factor analysis (EFA) and a confirmatory factor analysis (CFA) were conducted on the two samples respectively. Findings from the EFA suggest that this measure assesses three dimensions of Internet addiction: conflicts, mood modification, and dependence. Items in each dimension showed high internal consistency and acceptable test-retest reliability. Findings from the CFA further confirmed the three-factor measurement structure of CIAI. Test of criterion-related validity also showed good abilities for all three CIAI subscales to discriminate between an Internet addictive group and non-Internet addictive group. The theoretical and clinical implications of CIAI and its limitations are discussed.