Abstract: The syndrome of retained placenta or Retained Fetal Membranes (RFM) is an important economic problem that affects cows in the farms of Iran and many other countries. For determine of the best time for manual removal of fetal membranes, from September 2002 to September 2005 a total number of 200 RFM cows in the farms of Tabriz (north-west of Iran) were identified and randomly divided to 4 groups of A, B, C and D. In the groups of A, B and C the fetal membranes were pulled out by manual traction on days 6, 7 and 8 postpartum (Day of parturition = 0), respectively. The rates of complete or incomplete removal of fetal membranes were recorded in each group. In the group of D (group of control), the fetal membranes were not removed by hand and the mean time of spontaneous expulsion of fetal membranes in this group calculated as M = 10.8 days. In the groups of A, B and C, the rates of complete removal of fetal membranes were recorded as 52, 76 and 100%, respectively. Significant statistical differences (p<0.05) were observed between group of C (day of 8th postpartum) and other groups. These results indicated that, from technical point the day of 8th postpartum is the best time for manual removal of retained fetal membranes in the RFM cows. In other word, due to the high probability of fetal membranes rupturing and remaining of the part(s) of placenta in the uterus and following complication, traction of retained placenta, before the 8th day of postpartum, is not recommended in the RFM cows.