In the present study the effect of NaCl on morphological characteristics of Chlorella vulgaris Beijerinck was investigated. In order to evaluate the effect of NaCl, Chlorella was treated with different concentrations (0.1-0.4M) of NaCl, besides control. The study revealed that Chlorella vulgaris exposed over 30 days to different concentrations of NaCl exhibited marked morphological variations. At lower concentrations morphological variations were not pronounced but at higher concentrations distinct abnormalities such as enlarged cells with autospores, decolorized cells, inhibition of cell division, prominent increase in the diameter of the cells with shrunken chloroplast, cells with granular chloroplast and enlarged cells with disrupted chloroplast were noticed.