Present study was conducted to evaluate the effect butylated hydroxytoluene (BHT) on post-thawed semen quality of Beetal goat buck semen. Semen was obtained from six bucks using artificial vagina and cryopreserved in tris egg yolk extender and semen quality was assessed on the basis of post-thaw sperm motility, viability, plasma membrane integrity, and acrosomal membrane status. Ejaculates were pooled and extended to the concentration of 2 x 10(9) spermatozoa per mL in tris egg yolk extender (300 mOsmol/L). Tris egg yolk extender containing various concentrations of BHT (0.0, 2.0 and 5.0 mM) was prepared. French straws (0.5 mL) were manually filled with semen, gradually cooled from 39 degrees C to 4 degrees C and finally, cryopreserved in liquid nitrogen at -196 degrees C. Five straws from each treatment [BHT (0.0, 2.0 and 5.0 mM)] were thawed and evaluated under phase-contrast microscope (40 x) for sperm motility, whereas sperm viability, plasma membrane integrity and acrosomal integrity were assessed by the supravital staining, hypo-osmotic swelling test (HOST) and normal acrosomal reaction, respectively. The results showed that only acrosomal integrity was improved (P < 0.05) by the addition of BHT in semen extender. Motility was suppressed (P < 0.05) by increasing BHT concentration. The maximum motility of sperm was achieved with 0.0 mM BHT. The HOST response and viability of spermatozoa were increased by addition of 2 and 5 mM BHT, but this increment was not statistically significant. In conclusion, the addition of BHT to semen extender can partially improve semen quality of Beetal goat.