Background. It is unclear exactly how bariatric surgery affects the body’s metabolic and physiological functions. The purpose of the study was to assess the activity of growth hormone (GH) and insulin-like growth factor 1 (IGF-1) levels in obese individuals before and six months after laparoscopic sleeve gastrectomy. Materials and methods. This study included 52 patients with a body mass index (BMI) ranging from 35 to 56 kg/m2 who qualified for laparoscopic sleeve gastrectomy and had completed data at the 6-month postoperative follow-up. All patients were clinically examined by a team of surgeons and a physician before operation. The serum levels of GH and IGF-1 were assessed pre- and post-operatively. Results. The study included 52 patients with obesity who were undergoing laparoscopic gastric sleeve surgery. Their mean age was 32.04 ± 6.90 years. More than half of the patients, 27 (51.9 %), were aged 19 to 32 years, 32 (61.5 %) patients were females, and 38 (73.1 %) had a BMI of 35–49.9 kg/m2. There was a significant increase in the serum GH after the sleeve gastrectomy compared to the pre-operative level (0.95 ± 0.30 vs 0.62 ± 0.40 ng/ml, p = 0.0001). IGF-1 also significantly increased after the surgery: 117.13 ± 32.40 vs 102.63 ± 33.90 ng/ml (p = 0.0001). Concerning BMI, there was no significant difference in the GH mean for patients with a BMI of 35–49.9 and 50–56 kg/m2 pre- and post-operatively: 0.6 vs 0.8 (p = 0.07) and 0.9 vs 1 (p = 0.5), respectively. On the other hand, IGF-1 exhibited a significant difference before and after surgery: 107.7 vs 88.9 ng/ml (p = 0.02) and 123.2 vs 100.7 (p = 0.03). Conclusions. This study concludes that sleeve gastrectomy significantly increases the serum level of both GH and IGF-1 and, consequently, their effects on disturbed lipid and protein metabolism in morbidly obese patients.