The authors examined antibodies against antigen of gastric parietal cells using the method of reaction of complement-binding and the immunofluorescence test in 662 patients. Concurrently they examined in 443 patients of this group also antibodies against thyroglobulin. The group comprised 312 men and 350 women. For statistical evaluation the chi 2 test was used. Antibodies against the antigen of parietal cells were positive at the level of significance p less than 0.05 in the group with other diseases, at the level of significance of p less than 0.01 in dyspeptic syndrome, and at the level of significance p less than 0.001 in hypothyroidism and in chronic hepatopathies. The immunofluorescence test was statistically significant at the level of p less than 0.01 only in duodenal ulceration, at the level of p less than 0.001 in dyspeptic syndrome, hypothyroidism, hyperthyroidism, chronic hepatopathies, chronic pancreatitis, cholecystopathies, nephropathies and in the group of other diseases. Thyroid antibodies were positive with titres of p less than 1: 50 in 5.63, with titres of p less than 1: 5000 in 3.03%. The mentioned disease have not only pathomorphological and aetiological similarities but there is also serological overlapping.