Over recent decades, parasitic diseases have been increasingly considered a sanitary and economic threat to Mediterranean aquaculture. In order to monitor the distribution of parasites in cultured marine fish from Italy and study their pathogenic effects on the host, a three-year survey based on parasitological and histopathological exams was carried out on 2141 subjects from eleven fish species and coming from different farming systems (extensive, intensive inland farms, inshore floating cages, offshore floating cages and submersible cages). A number of parasitic species was detected, mostly in European sea bass (Dicentrarchus labrax), gilthead sea bream (Sparus aurata), mullets (Chelon labrosus, Mugil cephalus, Liza ramada) and sharpsnout sea bream (Diplodus puntazzo), with distribution patterns and prevalence values varying in relation to the farming system, in-season period and size category. The epidemiology and pathological effects of the parasites found during the survey are discussed.