In order to understand the factors which determine sea age of Atlantic salmon (Salmo salar), ovarian development of smolts was examined in 14 groups which varied in parental sea age, smolt age, and size. Parental sea age of smolts explained most of the variation in ovarian development. Smolts from one-sea-winter parents had a higher percentage of the more advanced oocyte stages in their ovaries, while smolts from two-sea-winter parents had a low percentage, and those from three-sea-winter parents had none. Annual within-stock variation and covariance with freshwater age were not significant. Hatchery-reared smolts had similar ovarian development to their wild counterparts. There was also a significant, positive correlation between fork length of smolts and ovarian development within groups.