The aim of this study was to determine the effects of egg yolk concentrations in freezing buck semen and conception rate following Al with frozen-thawed semen. Semen from 4 adult bucks was collected and diluted with 2.5, 5, 10 and 15% of egg yolk, frozen with a concentration of 200 million spermatozoa per 0.25 ml of straws. Sixty four Als were done with semen processed with each of 2.5 and 10% egg yolk concentrations in the diluent. Motility and morphology of the frozen-thawed spermatozoa were evaluated. Motility of semen (%) preserved with 2.5, 5, 10 and 15% of egg yolk were 50.3 ±1.2, 51.5 ± 0.5, 55 ± 0.7 and 56.8 ± 0.7, respectively. A significant ly (p<0.05) lower sperm motility was observed in semen preserved with 2.5 or 5% of egg yolk than that in 10 or 15% of egg yolk. The proportion of abnormal spermatozoa (%) were 15.4 ± 1.0, 13.1 ± 1.0, 10.9 ± 0.8 and 10.8 ± 0.6 in diluents with 2.5, 5, 10 and 15% of egg yolk. Acrosome integrity compromised significantly in the semen processed with 2.5 and 5% egg yolk than that of 40 and 15% egg yolk (p<0.05). Semen frozen with 2.5% and 10% of egg yolk produced conception rates of 39.1 and 48.4%, respectively. However, the difference in pregnancy rates was not significant. Increased concentration of egg yolk in the diluents provided better semen quality.