To determine the effects of insemination season (IS; dry: May through October and rainy: November through April), lactation number (LN; heifers, primiparous or multiparous) and their interaction on non-return rate (NRR), conception rate (CR) to first-service and pregnancy loss (PL) of Jersey cattle in Turkey, over 1468 lactation records from 510 Jersey dairy cows were used. There was an interaction between LN x IS on NRR, CR to first-service (p < 0.01) and PL (p < 0.05). The NRR and CR to first-service of heifers inseminated during dry season and of primiparous inseminated during rainy season were higher (p < 0.01) than that of multiparous inseminated during both season. The NRR and CR of heifers and primiparous were higher (p < 0.05) than that of multiparous cows. The insemination of heifers during rainy season and of primiparous and multiparous during dry season increased (p < 0.01) the PL compared to the inseminations of heifers during dry season and of primiparous during rainy season. The PL was lower (p < 0.05) in primiparous than multiparous cows. The results demonstrate that the heifers have high fertility than the lactating, especially multiparous and that IS appeared to have a measurable impact on traits relating to conception of Jersey cattle in the each LN.