A combination of reversed-phase high-performance liquid chromatography (RP-HPLC) and capillary zone electrophoresis (CZE) was used for characterization of alpha-chymotryptic digests of human pepsinogen A, human pepsinogen C (both isolated from stomach mucosa of patients suffering from gastric cancer), swine pepsinogen and their dephosphorylated forms. Combining RP-HPLC and CZE for peptide mapping allowed to detect phosphorylations in molecules of the above mentioned gastric zymogens. We have found one phosphate group in the molecule of human pepsinogen A and two phosphate groups in the molecule of human pepsinogen C. The investigated sample was obtained from stomach mucosa of a patient suffering from gastric cancer. An increased number of phosphate groups in molecules of human pepsinogen seems to be associated with gastric cancer. The developed method represent a suitable tool for studying relationships between specific phosphorylations of proteins and cancerogenesis or potentially could serve for early diagnosis of gastric cancer.