Meiofauna is a component of the marine benthos widely used in environmental impact studies, especially in coastal areas. A monitoring program of Admiralty Bay has been underway since 2008 (INCT-APA/CNPq), and in the summer of 2010, the meiofauna and the phytodetritus were sampled at two sites in three areas of Martel Inlet (CF, UP, BP) and at one area in Mackellar Inlet (RE). Densities were in the range of those found in previous studies in the bay and did not differ significantly between the eight sampling sites. Nevertheless lower densities (<3,000 inds. 4.9 cm 2) were found at one site in front of the Brazilian Station (CF1), under the influence of the sewage outfall, and at other three sites. Higher densities (>5,000 inds. 4.9 cm 2) were found at Ullmann Point (UP) and at one site in Botany Point (BP1). Nematodes were the dominant meiofauna group. A change in the meiobenthic community structure was detected at the site under the sewage outfall influence (CF1: low density, different composition), suggesting some influence of human activities on the benthic system in front of the Brazilian Station.