This study aimed at the adoption of an efficient method of heat detection in buffalo raised in large herds. For that, fourty two pluriparous buffalo calvers were used in this study. Calvings were distributed over a nine-months period extending from August, 1998 to May, 1999. The post-partum reproductive traits of the dry-season calvers (n=30) were compared to those of the green-season (n=12). The results of 92 heats, 110 ovulations and 671 peripheral blood samples (analized for P₄ concentration) were scrutinized. Heat detection was performed starting from the 2^nd week post-partum until the pregnancy was confirmed. Visual observation of estrus was conducted throughout the 24 hours of the day using a T.V-closed circuit unit. Heats were also detected using four types of detector animals i.e., a testosterone-treated buffalo cow, a testosterone-treated buffalo heifer (each was fitted with a chin-ball marking harness), a vasectomized buffalo bull and an intact buffalo bull. The overall mean of uterine involution period, post-partum ovulation interval, post-partum ovulatory heat interval, number of days-open and calving interval were 36.8±1.2, 39.0±3.6, 49.1±4.6, 75.6±4.5 and 392.2±0.4 days, respectively. The green-season buffalo calvers had significantly (P<0.05) lower incidence of quiet ovulations, higher conception rate-to the 1^st service and longer gestation period as compared to those of the dry-season calvers. The corresponding estimates of these traits were 10.0 vs. 16.4%, 83.3 vs. 60.0% and 323.0±2.2 vs. 314.1±1.8 days, respectively. Nevertheless, the conception rate after the 2^nd service and the ultimate calving interval did not show any significant differences due to season of calving. Heat detection efficiency (HDE) showed significant variations (P<0.05) among the different methods of heat detection used. The calculated estimates of HDE were 97.7% for the androgenized buffalo cow, 91.3% for the androgenized buffalo heifer, 87.1% for the vesectomized buffalo bull, 87.9% for the intact bull and 82.3% for the visual observation method. The corresponding efficiency estimated for detecting quiet ovulations were 82.8%, 65.5%, 41.4%, 44.8% and 0.0%, respectively. It has been shown that well managed buffalo cows raised in large-herds are capable to maintain regular reproductive capacity throughout the year-round. In these herds, the use of an androgenized buffalo cow fitted with a chin-bull marking harness could be suggested as an efficient, sanitary and economic method of heat detection.