Serum antibodies anti-Helicobacter pylori (H.p.) which are specific against antigenic determinants of the bacterial body, were determined in 183 non-ulcer dyspeptic children and adolescents, aged 7- to 20 years. 108 patients (59%) of the same group underwent fibroendoscopy for direct detection of H.p. in bioptic specimens of the stomach and duodenum microbiological methods. Discrimination analysis revealed a overall positive correlation between the results of the two methods: P < 0.01. For detection of specific IgG antibodies against H.p., evaluation by the P/N ratio was used, i.e. the absorbance of the examined serum (P) was compared with the mean absorbance of three negative serum controls (N). The specificity of the ELISA test in this examination was 96.1%, the sensitivity of 90.3%. The mentioned ELISA method for detection of specific IgG antibodies against H.p. is comparable with direct microbiological prove of H.p. presence in mucus specimens in our group examined. It is a very important non-invasive method useful for primary detection of H.p. infection.