Southern elephant seal, Mirounga leonina, populations at Península Valdés (Patagonia) and 25 de Mayo-King George I. were studied during the breeding season from 1979 to 1987. Two main objectives were taken into consideration: haul-out pattern and the female population trend. In both places, the intrinsic population growth rate is positive. In 1982, at Stranger Point, a sharp decrease of the female component of the population was observed (r=-56.54%). The recovery of the population at Stranger Point, and the global increase at Península Valdés, indicate the good condition of these populations.