Salinity is one of the major obstacles in enhancing rice production in growing areas in India. Salinity decreases germination percentage, speed of germination and led to reduction in shoot and root length and dry weight in all varieties of rice and the magnitude of reduction increased with increasing salinity stress. Therefore, development of salt tolerance varieties has been considered as one of strategies to increase rice production in saline prone areas. In this present study, adaptive response of Oryzae sativa L. to salinity stress was investigated. Seedlings of Oryza sativa showed significant reduction in different growth parameters studied i.e. seed germination, length of radicle and plumule, vigour index, fresh and dry weight of Oryza sativa seedlings with 100 mM NaCl concentration. The inhibitory effect of salinity stress was proportional to the exposure period and salt concentration. Maximum reduction in seed germination was observed with 100 mM NaCl solution at 72 h. Different concentrations of NaCl adversely affected the chlorophyll and protein contents in the seedlings of Oryza sativa in comparison to control. It has been observed that chlorophyll pigment in rice is very sensitive to salt stress. The depletion of biochemical constituents such as chlorophyll and protein contents under the influence of higher concentration of NaCl might cause inhibition in germination and growth characteristics of rice. The exogenous application of L-proline significantly decreased the effects of NaCl. Hence, it can be recommended that seeds of rice should be sown in the fields free from salt toxicity otherwise it will adversely affect the crop productivity.