This study was conducted to investigate corpus luteum`s responses and rate of conception following Lutalyse (PGF 2lk) administration and manual rupture of peristent corpus luteum in anestrus Holstein cows. The results obtained were as follows: 1. Lutalyse (PGF 2α) treatment for persistent corpus luteum showed better results in occurance of estrus, and rate of conception than those of manual ruptured. 2. Regressing of corpus luteum based on rectal palpation after Lutalyse administration showed within 24 hours in case of persistent corpus luteum, but after 48 hours in case of corpus luteum vevum. 3. Subcutaneous administration of Lutalyse showed better results in days upto estrus occurrence, percentage of estrus and conception rate than those of intramuscalar and vulvosubcutaneous administration.