Objective: To explore the feasibility of identifying potential radiometric differences in periapical radiolucencies with and without actinomycotic colonization as seen on periapical radiographs using histopathology for ground truth. Method and Materials: Periapical radiographs demonstrating apical lesions with and without biopsy-proven actinomycosis were included in the study. Lesion sizes were estimated on standardized images using anatomical reference points. The reading session was repeated after 2 weeks, and mean lesion sizes were calculated. All measurements were made by a single, calibrated observer. Results: The mean dimension of lesions with actinomyces was 13.51 × 16.43 mm, while lesions without actinomyces had a mean size of 10.24 × 11.27 mm. Conclusion: Apical lesions with biopsy-proven actinomyces may be larger in dimension than those without bacterial colonization. Further controlled studies are required to confirm this finding. Palabras clave: actinomyces, histology, intraoral, periapical, radiographic