Embryo survival was determined after non-surgical transfer to recipients with a variable synchrony of ovulation. Groups of 10 to 15 freshly weaned multiparous sows (donors and recipients) were checked and paired for time of ovulation, resulting in recipients ovulating from 24 h before to 36 h after the donors (‘asynchrony’ of −24 to 36 h). Embryos were collected from 34 donors at 120 h (range 108–132 h) after ovulation and 16.6±2.4 morulae and blastocysts were transferred to 31 recipients. Pregnant recipients were slaughtered on Day 35 (Day 0=ovulation) to evaluate embryonic survival. Twelve recipients were pregnant at Day 21 and five were still pregnant at Day 35. One recipient was excluded due to cystic ovaries. An asynchrony of 18 to 36 h resulted in 1/12 recipients pregnant at Day 21 and no pregnancies at Day 35, while an asynchrony of −24 to 12 h resulted in 11/18 recipients pregnant at Day 21 and five still pregnant at Day 35 (P<0.05). The presence of ≥6 morulae within a litter never resulted in pregnancies at Day 21 (0/9), while with <6 morulae, 12/21 recipients were pregnant at Day 21 (P<0.05), irrespective of the degree of asynchrony. The results seem to indicate that only blastocysts should be transferred successfully by a non-surgical procedure at 108 to 132 h after ovulation. Recipients should ovulate between 24 h before to 12 h after the donors. Transfers to recipients ovulating 18 to 36 h after the donors appear to lead to very low pregnancy rates. However, these conclusions need to be confirmed in a study with more animals.