Objective: To compare the techniques of immediate fixation and delayed fixation in detecting Helicobacter pylori (Hp) in gastric mucosal biopsies. Material and methods: We randomly selected gastric mucosal biopsies from 86 patients who attended the gastroenterology division at Belen Hospital (Trujillo) between November 2013 and June 2014. Four fragments of gastric mucosa were extracted from each patient, two were fixed immediately with 10% formaldehyde, and the other two were fixed after 24 hours (delayed fixation). Both samples were processed with the conventional technique of paraffin embedding and staining with hematoxylin-eosin (H&E) using Warthin-Starry as the gold standard. The presence of Hp was investigated in both fixation techniques. Results: It was found that the presence of Hp in H&E stained biopsies was greater in biopsies with delayed fixation (96.5%; kappa: 1,0) than in biopsies with immediate fixation (80.2%; kappa: 0,839); nevertheless, there was no statistically significant difference (p > 0.05). With respect to diagnostic value, the delayed fixation technique had a sensitivity of 100%, a specificity of 100%, a positive predictive value of 100%, and a negative of 100%; while the immediate fixation technique for detection of Hp in gastric biopsies had a sensitivity of 100%, a specificity of 76.5%, a positive predictive value of 94.5% and a negative of 100%. Conclusions: Delayed fixation technique showed higher values in the detection of Hp than the immediate fixation technique in gastric mucosal biopsies, although the difference was not statistically significant.