Cancer occurrence is associated with Arsenic (As) in drinking water. In Argentina, there are high As concentrations in groundwater but there is no published evidence yet of an association between geographic patterns of cancer incidence and the distribution of As in groundwater supplies. The purpose of this study is to assess the association between cancer incidence patterns and As in Córdoba province's aquifers. Age standardized incidence rates (ASIRs) were obtained from Córdoba Cancer Registry (CCR), and As data from official reports of monitoring wells. A multilevel model was applied. Total ASIRs by aquifers for males/females were 191.01/249.22 (Rioja plain); 215.03/225.37 (Pampa hills); and 239.42/188.93 (Chaco-Pampa plain). As was associated with increased risk of colon cancer in women, and lung and bladder cancers in both sexes. It had no association with breast cancer. ASIRs were related to As, controlling for unobserved heterogeneity. An overlapping pattern of higher As and higher risks was evident for lung, bladder and female colon cancers.