Abstract. In this research, biological material from 60 clinically healthy bronze turkeys at the age of 1, 7, 14, 28, 35, 49, 56, 90, 120 and 240 days were used. Six birds (3 male and 3 female) were included in each of the ten age groups. By means of electronic balance, the individual live body weights were determined and then, in full compliance with the requirements of the Ethical Committee at the Trakia University, Stara Zagora, a pair of Harderian glands was collected from each bird. Morphometric and weight investigations were carried out on each of the 120 glands collected. The results were statistically processed and presented in a table. The weight and morphometric research have shown that one-day old bronze turkeys possessed a Harderian gland weighing 7.30 mg, with a length of 8.50 mm, width of 2.16 mm and circumference of 3.66 mm. By the time of the sexual maturity and economic realisation (age of 240 days), the Harderian gland weight was 229.92 mg, its length – 24.60mm, width – 8.05 mm, and circumference – 16.81 mm.According to the results of the present study, the Harderian gland in common bronze turkeys has increased its weight almost 32 times 240 days after hatching. Its length was almost 3 times, its width – 4 times and its circumference – 6 times higher as compared to the age of one day.