Background: Third molars of mandibula are the last teeth that have erupted and often impacted. Impacted teeth can cause pathological abnormalities such as caries, infections, periodontal problems, pericoronitis, neoplastic lesions, cysts, androot resorption. The impact of third molars of mandibular and their accompanying pathological abnormalities can be observed by using radiographywith panoramic. Objective: To find out the prevalence of impaction of mesioangular third molars causing distal caries of second molars ofmandibular according to Pell and Gregory classification through panoramic radiographic observations at Dental and Oral Hospital of Universitas Airlangga. Material & Methods: Data of study based on secondary data form 49 panoramic digital radiographs observed by the impact of mandibular mesioangular third molars and classified according to Pell and Gregory to determine the class and position that most often causes distal caries in the second molars. To analyze and processed the data of this study using Friedman test. Results: Class and impact position of mandibular mesioangular third molars were found to be 55% at position IIA, 23% at position IIB, 18% at position IA and 5% at position IB. Distal caries in the second molar teeth 69% occurred in the impacted mesioangular third molar teeth, position IIA, followed by the IA position as much as 19%, then the IIB position as much as 10% and the IB position as much as 2%. Conclusion: Abnormalities ofpathological in the form of distal caries of the second molar through panoramic radiography were found most at position IIA, second at position IA, then position IIB, and only slightly at IB position.