We investigated the influence of exposure to chronic salinity (NaCl) and mifepristone (a glucocorticoid antagonist) for 24 d on wet mass (g), dry mass (g; following freeze drying), water content (%; calculated after freeze drying), snout-vent length (mm), and developmental stage (Gosner stage) of Northern Leopard Frogs (Rana pipiens). The dataset contains values of each trait for each larva that was alive on the final day (day 24) of the experiment