Drought is the major abiotic stress, which often adversely affects plant growth and productivity. Plant responses depend on the type of stress, species, and genotype. Proline is one of the most common compatible osmolytes in water-stressed plants. It is a common physiological response in many plants in response to a wide range of biotic and abiotic stresses. This 278study was undertaken to identify physiological changes in seedlings of four onion cultivars (Prema-178, Arka kirthaman, Bellary, and Arka Lalima). The experimental design was randomized entirely, with different concentrations of polyethylene glycol – 6000, i.e., 0, 25 g/L, 50 g/L, 75 g/L, and 100 g/L for different time intervals (0, 8, 24, 48, and 72 h). Our results in cultivars of onion gave a positive correlation between proline accumulation verses induced drought treatments. We observed a significant increase in proline accumulation up to 48 h and then decrease at 72 h in all cultivars at different concentrations. The increase in proline accumulation was three-fold at 48 h. Further studies are required to identify the tolerant variety suitable for local climatic conditions. The germplasm of the tolerant variety will be used in creating more tolerant variety with high productivity and yield.