We aim to describe rates and risk factors of Hepatitis C Virus (HCV) diagnoses, follow-up HCV testing and HCV seroconversion from 2004-2011 in a cohort of HIV-positive persons in Spain. CoRIS is a multicentre, open and prospective cohort recruiting adult HIV-positive patients naïve to antiretroviral therapy. We analysed patients with at least one negative and one follow-up HCV serology. Incidence Rates (IR) were calculated and multivariate Poisson regression was used to estimate adjusted Rates Ratios (aIRR). Of 2112 subjects, 53 HCV diagnoses were observed, IR = 0.93/100 py (95%CI: 0.7-1.2). IR increased from 0.88 in 2004-05 to 1.36 in 2010-11 (aIRR = 1.55; 95%CI: 0.37-6.55). In men who have sex with men (MSM) from 0.76 to 1.10 (aIRR = 1.45; 95%CI: 0.31-6.82); in heterosexual (HTX) subjects from 1.19 to 1.28 (aIRR = 1.08; 95%CI: 0.11-10.24). HCV seroconversion rates decreased from 1.77 to 0.65 (aIRR = 0.37; 95%CI: 0.12-1.11); in MSM from 1.06 to 0.49 (aIRR = 0.46; 95%CI: 0.09-2.31); in HTX from 2.55 to 0.59 (aIRR = 0.23; 95%CI: 0.06-0.98). HCV infection risk was higher for injecting drug users (IDU) compared to HTX (aIRR = 9.63;95%CI: 2.9-32.2); among MSM, for subjects aged 40-50 compared to 30 or less (IRR = 3.21; 95%CI: 1.7-6.2); and among HTX, for female sex (aIRR = 2.35; 95%CI: 1.03-5.34) and <200 CD4-count (aIRR = 2.39; 95%CI: 0.83-6.89). We report increases in HCV diagnoses rates which seem secondary to intensification of HCV follow-up testing but not to rises in HCV infection rates. HCV IR is higher in IDU. In MSM, HCV IR increases with age. Among HTX, HCV IR is higher in women and in subjects with impaired immunological situation.