OBJECTIVE:: To assess the potential utility of in vivo histologic surface and subsurface imaging in real-time using the Optiscan confocal laser microscope to detect diseased tissue at the time of surgery. SUMMARY BACKGROUND DATA:: The goal of surgical treatment of diseases such as cancer is complete microscopic resection of diseased tissue; however, current methods for the assessment of extent of disease at the time of surgery are inadequate. METHODS:: We assessed the potential of the Optiscan confocal laser microscope, a new device developed for real-time in vivo histologic surface and subsurface imaging during surgery. RESULTS:: Intravenous Fluorescein Sodium contrast enabled visualization of cellular and architectural morphology of intra-abdominal organs with magnification equivalent to light microscopy and enabled differentiation between normal organs and disease. CONCLUSIONS:: Real time intraoperative confocal microscopy has significant potential application in detecting disease, and influencing decision-making at the time of surgery.