Abstract: The experiment was conducted to compare the relative efficiency of homo and heterospermic insemination in respect of fertility judged by conception and calving rate. Spermatozoa from three different breeds of bull namely Holstein Friesian (HF), Red Chittagong (RC) and Sahiwal (SL) were mixed in equal number and preserved for 3 days and inseminated at different days. In this study 168 cows were inseminated and 42 of them were inseminated with heterospermic semen containing equal numbers of spermatozoa from a HF, a RC and a SL bull. After calving the paternity of calves was established by comparing coat colour and conformation. Difference between homo and heterospermic insemination on conception and calving rate was not significant (p>0.05). The heterospermic conception and calving rates were 80.95 ±0.07 and 64.29 ± 0.08%, with the homospermic rates being 66.67 ±0.04 and 50.79 ±0.04%, respectively. The conception and calving rate from heterospermic insemination was found insignificantly (p>0.05) different from that of homospermic insemination separately at first, second and third day of preservation. Conception rates of homo and heterospermic insemination at first day were 76.19 ±0.07 and 85.71 ±0.12%, respectively. The corresponding values at third day were 59.52 ±0.07 and 78.57 ±13%. Calving rate of homo and heterospermic insemination at first day were 57.14±0.08 and 64.29 ±0.13%, respectively. The corresponding values at third day were 45.24 ±0.08 and 64.29 ±0.13%. The numbers of offspring (12:8:7) sired by the three bulls (HF: RC:SL) after using heterospermic semen did not differ significantly from an assumed 1:1:1 ratio (χ2 = 1.55: p>0.05). The sex ratios among calves from heterospermic insemination (15♂ .12♀) also did not differ significantly (χ2 = 0.34: p>0.05) from 1:1. From the above results, it was concluded that heterospermic insemination did not however, show any significant superiority in conception and calving rate in cows compared to homospermic insemination. However, heterospermic insemination offers no apparent risk to co-operating farmers, since overall conception and calving rate were either numerically higher or at least equal to that obtainable from homospermic insemination.