The aims of this study were to ascertain if individual turbot (Scophthalmus maximus) females show a seasonal decline in their egg-size when kept in conditions of constant temperature, and to relate turbot egg-size to the length and yolk-sac index of the emergent larva. Each female showed a significant seasonal egg-size decline and there was a positive correlation between egg-size and the length and yolk-sac index of the subsequent larva. However, larval length was not related to yolk-sac index, nor was the ratio of yolk-sac index:larval length related to egg-size. The maximum mean egg-size tended to increase with the female's weight and length. The implications of these findings are discussed in terms of the general ecology of turbot and its culture.