The present study aimed to evaluate the effect of vitamins AD₃E administration during different seasons of the year in Egypt on physiological thermoregulatory response, blood components and semen characteristics of Damascus bucks. Thirty Damascus goat bucks aged 14-15 months and weighing 32-35 kg were divided into three similar groups (10 bucks in each). The first group (Control, G1) was kept without treatment (injected by saline solution (, while the second (G2) and third (G3) groups were injected intramuscularly biweekly with vitamin AD₃E at levels of 2 and 4 ml/buck, respectively. Thermoregulatory parameters, some Blood component and hormones, Semen characteristics, semen storage ability and Scrotal measurements were measured biweekly. The treatment period lasted during different seasons for one year. Results showed that hair, skin, rectal, scrotal skin, and ear temperatures were the highest (P<0.05) in summer and the lowest (P<0.05) in winter, but these traits were not affected by vitamins injection.  Concentrations of total protein (TP), albumin (A), Ca and P decreased (P<0.05) in summer compared with other seasons, while globulin (G) concentration increased (P<0.05) in summer and autumn compared with winter and spring. Concentrations of TP, G, Ca and P increased (P<0.05) by vitamins injection. Concentration of testosterone was the highest (P<0.05) in autumn and the lowest (P<0.05) in summer. The highest (P<0.05) T₃ and T₄ levels was in winter . Cortisol concentration was highest (P<0.05) in summer and the lowest (P<0.05) in winter and autumn. Concentration of testosterone, T₃ and T₄ increased (P<0.05), while cortisol concentration decreased (P<0.05) by vitamins injection.  No significant changes in scrotal circumference were observed due to change of season or due to vitamins injection. The highest testicular length was in bucks injected with 4 ml vitamins while the lowest testes length was in control bucks. Testes size increased (P<0.05) by increasing level of vitamins injection.  The lowest (P<0.05) number of ejaculate and semen volume were in summer, while the highest values were in autumn. Number of ejaculate, libido and semen volume increased (P<0.05) by vitamins injection and the opposite trend was observed in pH value. The highest motility percentage and the lowest dead sperm, abnormality and acrosomal damage percentages were during autumn while the lowest motility percentage and the highest dead sperm, abnormality and acrosomal damage during summer. Semen characteristics including percentages of mass motility, dead sperm, abnormality and acrosomal damage improved (P<0.05) by vitamins injection. The best semen storage ability was in autumn. From these results it can be concluded that vitamins AD₃E injection improved semen quality of heat stressed goats bucks, especially at a level of 4 ml/buck.