Lifetime reproduction of 1462 eight-year-old Karakul ewes was recorded since 1972. The influence of season of birth, age at first lambing and lambing interval on lifetime reproduction was investigated Age at first lambing was significantly (P<0,01) affected by month of birth (R2 = 36%), with spring-born ewes lambing at a younger age than summer- or winter-born ewes. Lifetime reproduction was influenced by both age at first lambing and average lambing interval (R2 = 20%). However, first lambing interval was unimportant as a predictor of both lifetime reproduction and average inter-lambing periods, with a non-significant (P >0,05) correlation estimate (r =0,05) between first and average interlambing periods. The inclusion of age at first lambing in a selection programme was recommended.