Investigations were carried out on the diversity of phytoplankton in relation to physico-chemical parameters with respect to water quality status of a subtropical pond, "Datte da Talab in J&K. The physico-chemical parameters showed well-marked seasonal variations. A total of 21 genera belonging to three different groups (Bacillariophyceae, Chlorophyceae and Cyanophyceae) were recorded during the study period with maxima in winter season and minima in summer season. Qualitatively and quantitatively Bacillariophyceae dominated all other classes followed by Chlorophyceae and Cyanophyceae. No apparent differences were found in phytoplankton composition at all the sampling sites. Phytoplankton community when correlated with physico-chemical parameters indicated that the distribution and density of phytoplankton species was influenced by physical and chemical factors of the pond environment. Phytoplankton showed significant correlation with certain abiotic parameters such as water and air temperature, phosphates, carbonates and chlorides. The various kinds of indices such as Margalef's index, Menhinck's index, Simpson index, Shannon- Wiener index and Equitability index were used to support the data.