To investigate cancer risk in dockyard workers exposed to carbon black. Cancer incidence was ascertained among 2101 longshoremen employed at the dockyard of Genova, Italy They were categorized a priori as exposed to low, moderate, and high level of carbon black dust. Incidence rates for the male population of the City of Genova were used to compute standardized incidence ratios (SIR). A positive exposure-response relation with carbon black exposure was detected only for bladder cancer (SIR = 204, 95%CI = 112-343, in highly exposed workers). Increased incidence of pleural mesothelioma (SIR = 751, 95%CI = 302-1547) and melanoma (SIR = 288, 95%CI = 125-2168) were detected. Exposure to carbon black experienced by dockyard workers was associated with a two-fold increased risk of bladder cancer. Copyright 2004 Kluwer Academic Publishers