Background: Gastric cancer represents a major cause of death worldwide. White light endoscopy with biopsy is the well-established modality in detection of gastrointestinal lesions but not frequently correlated with histological alterations. Probe based confocal laser endomicroscopy (pCLE) and Narrow band imaging with magnification (NBI-ME) have been suggested to enhance the accuracy of endoscopic surveillance of the gastrointestinal tract. However, its potential in assessing gastric histology has not been compared systematically. Aim of the work: This study was conducted to compare efficacy of pCLE with the efficacy of NBI-ME and High Resolution white light Endoscopy (HR-WLE) for the early detection of gastric mucosal precancerous and cancerous lesions. Design: The study was conducted on 32 patients presenting to Berlin and Hamburg university Hospitals with dyspepsia or anaemia. All patients firstly underwent white light upper endoscopy. Secondly five random spots in the stomach (two in antrum, two in corpus and one at the incisura angularis) including mucosal abnormalities if present, were marked by an Argon plasma beamer. Subsequently, the gastric mucosa adjacent to these designated spots was examined by HR-WLE, NBI-ME followed by pCLE. Thereafter, tissue specimens were obtained from each spot using a conventional biopsy forceps. Then, the sensitivity, specificity, PPV, NPV and kappa scores of HR-WLE, NBI-ME, and pCLE for diagnosing precancerous and cancerous gastric mucosal lesions were calculated. In addition, the quality of NBI-ME images and pCLE images was assessed.Results: Gastric intestinal metaplasia (GIM) diagnosed in 23 biopsies was evident by pCLE in 21 sites, in 1 by HR-WLE and in 15 by NBI-ME. Sensitivity, specificity, positive and negative predictive values were 91, 98.5, 91 and 98.5 % for pCLE and 65, 98, 83 and 94% for NBI-ME, respectively. Gastric mucosal atrophy (GMA) was found in 10 biopsies by histopathological work up; 6 of which could be classified by pCLE, 2 by HR-WLE and 3 by NBI-ME. Sensitivity, specificity, positive and negative predictive values were 60, 100, 100 and 97 % for pCLE and 30, 99, 75 and 95.5% for NBI-ME, respectively. Gastritis was found in 90 biopsies by histopathological work up; 53 of which could be detected by pCLE, 28 by HR-WLE and 50 by NBI-ME. Sensitivity, specificity, positive and negative predictive values were 59, 76, 76 and 59 % for pCLE and 56, 84, 82 and 60% for NBI-ME, respectively. Kappa scores for the diagnosis of the GIM, GMA and gastritis were 0.89, 0.73 and 0.38 (pCLE), 0.69, 0.4 and 0.38 (NBI-ME) and 0.07, 0.1 and 0.38 (HR-WLE) respectively.Conclusion: Evaluation of images acquired by pCLE enables correct assessment of gastric histology with high accuracy and proves to be superior to NBI-ME and HR-WLE.