Distribution, abundance and species assemblages of Phytoplankton were studied from inshore waters of Nizampatnam, South East coast of India in March 2007. Significant spatial variations in temperature, pH, salinity, dissolved oxygen (DO), nitrites (NO₂) –N), nitrates (NO₃) – N), phosphate (PO₄) –P), silicate (SiO₄) – (Si) were monitored. A total of 90 species of phytoplankton (net hauls) represented by 5 groups were identified at nine stations, collected along three transects during low tide. Percentage contribution of each group of phytoplankton was in the order: Bacillariophyceans > Dinophyceans > Cyanophyceans > Euglenophyceans. Pleurosigma angulatum, Navicula sp. were dominant species in the study area. Bray - Curtis similarity and group average clustering, recommended identifying two assemblages of phytoplankton in the study area. High diversity of phytoplankton in the present area suggests stable environmental conditions.