Prostaglandin F2 alpha (PGF2 alpha) (2 doses, 11 days apart) was given to 20 mixed-breed dairy does to synchronize estrus and ovulation. The dose of PGF2 alpha used was the free-acid equivalent of 8 mg which was divided between 2 injections at 0800 and 1200 hours. At the initiation of treatments, does were from day 0 (estrus) to day 18 of the estrous cycle. Seventeen of the doses exhibited estrus within a mean (+/- SE) interval of 53 +/- 2 hours after the first 0800-hour injection. Peripheral progesterone concentrations determined at daily intervals indicated that PGF2 alpha was luteolytic as early as day 4 of the cycle. Does were in the 8th to 12th days of the cycle at the time of the 2nd treatments with PGF2 alpha. Estrus was observed in all 20 does at 50 +/- 1 hour after the 0800-hour injections. Serum progesterone concentrations confirmed that luteolysis occurred in all of the does. In 19 does, concentrations of luteinizing hormone characteristic of a preovulatory peak were observed 55 +/- 2 hours after the 2nd 0800-hour injection. One doe did not demonstrate a luteinizing hormone peak within the 72-hour period. Laparotomies were performed 6 days after estrus, and ovaries were examined for corpora lutea. The mean number of corpora lutea was 2.0 +/- 1.0.