Pregnancy and early embryonic death rates in cycling and noncycling progesterone-treated recipient mares were examined in a retrospective study. During three breeding seasons, 264 embryos were transferred into either cycling (control, n=152) or noncycling (n=112) mares in a commercial embryo transfer program in Brazil. The anovulatory mares were treated with either 200 mg/day (Treatment 1, n=54) or 400 mg/every other day (Treatment 2, n=13) short acting progesterone, or 1500 mg long acting progesterone every 7 (Treatment 3, n=30) or 6 (Treatment 4, n=15) days. Embryos were transferred non-surgically into cycling recipients 4 to 8 days after ovulation and 5 to 8 days after the beggining of progesterone supplementation into anovulatory mares. Pregnancies were checked on days 12, 25 and 50 by transrectal ultrasonography. Data were analyzed by Chi-square. Pregnancy rates on days 12 (75.0, 75.9, 76.9, 76.6 and 73.3%) and 50 (61.8, 61.1, 61.5, 53.3 and 60.0%) as well as embryonic death rates (17.5, 19.5, 20.0, 30.4 and 18.2%) were similar (P>0.05) for control mares and treatments 1, 2, 3 and 4, respectively, and between control and all anovulatory mares combined. Concerning pregnancy and embryonic death rates in anovulatory recipients, similar (P>0.05) results were obtained after embryo transfers into recipients receiving short or long acting progesterone for 5 to 8 days before transfer, as well as after transfers performed during spring or fall and during winter. Additionally, daily administration of short acting injectable progesterone provided similar (P>0.05) results as administration of a high dose (400 mg) on alternate days. In conclusion, anovulatory mares treated with short or long acting progesterone for 5 to 8 days before transfer can be successfully used as embryo recipients during the period of the year in which few cycling recipients are available.