The objectives were to (1) evaluate the associations between plasma progesterone (P4) concentration after first service and reproductive outcomes and (2) examine the associations between genetic traits and plasma P4 concentration. First and second lactation spring calving dairy cows (n = 915) from 35 dairy farms located in Ireland were enrolled in the study. Plasma P4 (ng/mL) was determined from a single blood sample collected at either 7 (n = 475) or 13 (n = 440) d after first insemination at detected estrus (FAI). The fertility sub-index of the Economic Breeding Index and the predicted transmitting ability (PTA) values for the individual traits calving interval (CIV), survival, milk kg and percentage protein in milk were obtained from Irish Breeding Cattle Federation, and cows were stratified into quartiles. For continuous data, the normality of both the raw data and residuals was tested, and where transformation was necessary the most appropriate Box-Cox transformation was implemented. GLIMMIX procedure was used to determine the associations between plasma P4 concentration, reproductive outcomes and individual genetic traits including herd, year and parity as fixed effects. Plasma P4 at 7 and 13 d after FAI was positively associated with likelihood of pregnancy after FAI (P = 0.05 and P = 0.001, respectively). The PTAs for milk kg and survival were positively associated with plasma P4 at d 7 (P = 0.02 and P = 0.01, respectively) and d 13 after FAI (P = 0.05 and P = 0.004, respectively), and cows in the quartile with greatest PTAs for milk kg and survival had greater likelihood of pregnancy after FAI compared with the other quartiles. Cows in the quartile with greatest fertility sub-index and smallest CIV tended (both P = 0.10) to have greater plasma P4 at d 7 and 13 after FAI compared with the other 3 quartiles. In conclusion, plasma P4 at 7 and 13 d after FAI were associated with individual genetic traits and reproductive outcomes. Supported by Irish Department of Agriculture, Food and the Marine (Grant 13S528).