Fecundity estimates were made on 428 mature herring (Clupea harengus harengus L.) (maturation stages 4 and 5) collected from the southern Gulf of St. Lawrence and the Nova Scotia coast. Estimates ranged from 23,000 to 261,000 eggs per female. Fecundity increased exponentially with the fish length and weight at different rates for different herring stocks. Values of the exponent ranged between 3.7–5.3 and 1.1–1.6 for length and weight, respectively. Results of regression analyses showed that fecundity depended more on fish weight and length than on age.