80 patients with gastroesophageal reflux disease (GERD) were examined. The diagnosis of GERD was based on the history of the disease, complaints of patients, the results of daily monitoring of pH in the lower third of the esophagus, data of fibroesophagogastroduodenoscopy, chromoendoscopy, 13C-octanoic breath test, gastrin-17 (G-17) concentration, pepsinogens I and II (P I and II) and cholecystokinin-pancreozymin (C-P) in serum.After 24 hours pH monitoring of the lower third of the esophagus in 40 patients with GERD, the predominance of acid was found, and the other 40 patients had mixed refluxes. In patients with predominance of acid reflux, the mean values of half-life of solid food evaluation (T1/2) according to 13C-octanoic breath test was (45.25±1.34) min. With the predominance of mixed refluxes in patients, there was a tendency towards hypokinetic motility of the stomach, indicating a slowdown in half-life of solid food evaluation from the stomach up to (139.24±11.87) min. With the predominance of acid reflux also was observed a significant reduction in the concentration of G-17 and C-P, an increase in P I and a decrease in the concentration of P II. Hypergastrinemia, high levels of C-P and P II (37.44±3.41) μg/l (p<0,05) were diagnosed with the predominance of mixed refluxes.