The substantiation of the use of antioxidant compounds to correct the reproductive capacity of males is an urgent problem of modern reproductive science. Some amino acids have pronounced antioxidant properties, including N-acetylcysteine (NAC). The work aimed to determine the effect of oral administration of NAC on sperm quality and hormonal balance in infertile boars. According to the results of andrological dispensation, three groups of animals were formed – I experimental groups (n = 5) and II (n = 5), with reduced reproductive capacity, and control (n = 5) with total reproductive capacity. The animals of the experimental groups were orally administered NAC at a dose of 75 mg/kg body weight (test I) and 50 mg/kg body weight (test II) for 30 days. With the introduction of different doses of NAC, an improvement in the quality of the ejaculates of the boars of the experimental groups was observed. In I experimental group, on the 120th day of the experiment, a probable increase in motility by 35.5 %, ejaculate volume by 8.7 %, and concentration by 5.1 % were established (P ˂ 0.05). On the other hand, the content of spermatozoa with morphological abnormalities probably decreased (by 22.7 %, P ˂ 0.01). Similar changes were obtained in boars of the II experimental group – the number of morphologically abnormal cells probably decreased – on the 90th and 120th day of the study by 17.7 % (P ˂ 0.05) and 24.7 % (P ˂ 0.01), respectively. Sperm motility and ejaculate volume increased significantly – by 28.1 % (P ˂ 0.01) and 7.9 % (P ˂ 0.05). The use of NAC contributed to the normalization of the endocrine function of the gonads, as a result of which an increase in the level of total testosterone in the blood serum of boars – an experimental group I was established by 16.3 % (P ˂ 0.05) on the 30th day of the study and by 33.7 % (P ˂ 0.001) on the 45th day. Similar changes were obtained in the animals of the II experimental group – an increase in testosterone level by 13.8 % and 29.8 % on the 30th and 45th day of the experiment, respectively (P ˂ 0.05–0.01). The estradiol level tended to decrease on the 30th day of the study. In contrast, on the 45th day, it was significantly lower than before administration by 13.6 % and 12.3 % in animals of I and II experimental groups, respectively (P ˂ 0.05). Testosterone-estradiol ratio up to 7.4–8.2 units on the 45th day of the study, which indicated the normalization of the balance of sex hormones in the body of boars. The obtained results recommend NAC as an effective means of correcting infertility in boars.