Sex ratios are presented for 4,802 northern pike captured by nets, electrofishing, and angling from three Ontario populations. Anglers captured more female than male northern pike (1.24:1) and a higher ratio of female fish than were taken by other methods (1.14:1). Regardless of method or region of capture, sex ratios showed similar seasonal trends. Males were relatively more abundant during two seasons—spring and autumn—when the sex ratios were approximately equal. Often 1.5 to 2.0 times as many females as males were present during summer and winter in anglers' catches and net samples. There was no significant difference between either the summer (1.44:1) and winter (1.27:1), or the spring (1.04:1) and autumn (0.98:1), sex ratios. The sexes appear to have biannual peaks of availability which are related to activity and are independent of locality and method of capture.