Biopsy Specimens of human gastric mucosa of patients subjected to endoscopic examination were cultured microaerobicallY in MHB or MHC selective media at 37℃. Campylobacter pyloridis (Cp) was isolated in 8l out of 116 cases (69.83%), including 61 out of 85 patients with gastritis (71.76%), 13 out of 15 with peptie ulcer (86.67%) and 7 out of 9 with gastric carcinoma (77.78%). Nothing was detected in 7 cases of normal gastric mucosa. The features of the colony and microscopic morghology, phology, Stain and biochemical reactions and ultrastructure of the isolates corres-ponded with those of Cp. It is suggested that Cp can be routinely iden-tified by its colony characteristics, bacterial morphology, stain reactions and the rapid urease test. The factors influencing the isolation rate of Cp and reasons fo some probable differences in the ultrastructure are also discussed.