We studied tumor detection by indocyanine green (ICG) with near-infrared topography in rat experimental tumors: hepatoma AH109A and osteosarcoma POB 102. Time-intensity curves and topograms after ICG injection were obtained in tumors and surrounding normal tissues. Intensities in tumors were slowly reduced, and intensities in normal tissues were rapidly reduced, resulting in positive tumor image in topogram. It is concluded that near-infrared topography enhanced by ICG is useful for cancer detection.