there are few environmental studies using biomarkers for the species atherinella brasiliensis in brazil. in the present work, the presence of hepatic histopathological lesions and nuclear abnormalities in erythrocytes were investigated in a. brasiliensis from lamberto, a beach under influence of domestic wastes and marine activities. for comparison, fish were also sampled in puruba, a non-polluted beach, located in the northeastern of s？o paulo state. the frequency of lesions found in liver was in higher numbers in individuals from lamberto than puruba beach. the most critical injuries observed in a. brasiliensis were the presence of necrotic areas, leucocytes infiltration and piknotic nucleus. a high occurrence of cells with vacuolization was also observed. the hepatic lesion index of the fish from lamberto beach showed significant high values (iorg=13) when compared with fish from puruba beach (iorg=7) suggesting the influence of the several human activities in the studied site. notched and blebed nucleous were observed in this study, and significant differences were found between the studied sites. however, these differences did not reflect the total nuclear alterations.