Sodium arsenite (NaAsO₂) is a potent inhibitor of germination and growth of mungbean (Vigna radiata (L.) Wilczek cv. B-105) seedlings. With the increase in concentration of sodium arsenate (0.5μM, 1μM and 2μM) significant decrease in seedling length and primary leaf area was observed. Photosynthetic metabolism was markedly affected. Photosynthetic pigments like Chlorophyll a, b, total chl. content, carotenoid content and non cyclic electron transport or Hill activity of chloroplasts reduced appreciably in the sodium arsenite treated seedlings. Perturbations in carbohydrate synthesis were evidenced by the reduction in reducing sugar and non-reducing sugar content of the seedlings whereas the starch content was found to be elevated. Thus, Arsenite induced stress leads to lesser growth and development of the important pulse crop, Mungbean.