Effects of age, period and birth cohort on consumption of fat fish, lean fish and processed fish were estimated based on panel data from the Norwegian Women and Seafood Consumption Study (NOWAC). Cohorts selected for the present analysis were women born between 1951 and 1966. Survey questionnaires were mailed to a stratified random sample from the Norwegian population registry in 1996 and 2001. Complete data sets for both periods were obtained from N = 4590 respondents. Data were analyzed by means of multivariate linear models. Results indicate that overall consumption of fat fish and processed fish increased between 1996 and 2001, while consumption of lean fish decreased. All three period effects were stable across birth cohorts. Estimation of polynomial contrasts indicated that birth cohort itself had linear effects on consumption, with older generations consuming significantly more fat and lean fish, but less processed fish than younger generations. Finally, the effects of cohort and period on consumption of lean and processed fish remained stable when biological age was controlled for, whilst the effect of period on fat fish consumption vanished. Regarding total consumption of fat fish, the relative size of the effects suggests that either (a) a positive effect of period is neutralized by a negative effect of birth cohort, resulting in a zero net effect for the period under investigation, or (b) that both effects are peripheral, caused by an underlying biological-ageing effect. Total consumption of lean fish, on the other hand, is clearly falling in Norway, whereas total consumption of processed fish is rising, suggesting clear areas for marketing action.