Oxygen nonstoichiometry and electrical resistance of a series La2-xSrxNiOy solid solutions, where x = 0.0, 0.2 and 0.5 in argon flows at oxygen partial pressures 1.5, 10.2, 49.2, 100 and 286 Pa within the temperature range of 20-1050 degrees C were studied. Nickelate oxygen desorption/sorption spectra when heating-cooling at constant rate demonstrated strong dependence of cation composition of the samples. Unlike La1.5Sr0.5NiOy compounds those of La2NiOy and La1.8Sr0.2NiOy have weakly bonded oxygen, capable to exchange reversibly with the gas phase at the temperatures higher than 250 degrees C. The equilibrium values of oxygen nonstoichiometry and specific resistance for the these nickelates were determined at 300-1050 degrees C and p(O2) = 1.5-286 Pa as a functions of temperature versus oxygen partial pressure. All nickelate studied appear to be p-type conductors with metal electric conductivity at equilibrium states.