Caries and its complications take the leading role in the development of gastrointestinal diseases in young people. Gastroesophageal reflux disease is one of the most common diseases of the digestive tract. An important role among the components of the immune defense of the oral cavity belongs to non-specific humoral factors produced by various cells that act in a complex, which increases the final effect of protection. Aim of the study - to determine the indices of local immunity in patients who had combined dental pathology (caries) and gastroesophageal reflux disease. In total were exanimated 33 patients with dental caries in age from 18 to 25 years, including 21 men and 12 women. The main group consisted of 17 patients who had a combined dental pathology (caries) and gastroesophageal reflux disease. The comparison group consisted of 16 people who had dental caries without other systemic diseases. All patients, who were included in the study was carried out the following researches: a study of the dental status, an immunological study for all patients with the determination of a quantitative assessment of the main populations and subpopulations of lymphocytes, determination of their functional activity, determination of level of serum immunoglobulins, determination of the concentration of circulating immune complexes of various molecular sizes, phagocytic activity of neutrophils and cytokine status in serum and oral fluid, as well as assessment of the course of gastroesophageal reflux disease with questionnaires. The results of the values of the resistance of hard tissues to the effects of cariogenic factors had a high positive correlation with the intensity of dental caries lesions. That confirms the presence of a relationship between manifestations of systemic diseases together with the development of dental caries, especially against the background of a decrease in caries resistance. In the presence of gastroesophageal reflux disease in patients dental caries detected spontaneous activation of lymphocyte proliferation by 25.8%, an increasing of the phagocytic activity of neutrophils, detected significantly higher indicators of the phagocytic number and phagocytic index, increased content of medium and small molecular circulating immune complexes with pathogenic properties. Detected significantly higher content of pro-inflammatory cytokines - tumor necrosis factor-α, an increased concentration of IgG as a result of antigenic stimulation, and also a significantly lower concentration of secretory IgA. It has been established that in patients with gastroesophageal reflux disease combined with dental caries observing changes in the immune system, which bear the features of subclinical immune inflammation. The study revealed a higher intensity of the carious process in patients with gastroesophageal reflux disease, which is associated with permanent acid damage of the oral mucosa. Furthermore, it was found violation in terms of concentration with increasing local immunity oral liquid proinflammatory factors and a reduced concentration of secretory IgA namely with concomitant pathologies of the gastroesophageal reflux disease.