Abstract: A method and apparatus for examining a cell smear for the purpose of detecting the presence of cancerous and precancerous cells located therein. In a preferred embodiment, the method comprises illuminating at least a portion of the cell smear with light of a first wavelength, whereby native fluorescence is emitted therefrom. Next, the intensity of native fluorescence emitted from the illuminated area is measured at a second wavelength and at a third wavelength as a function of location within the illuminated area. The first, second and third wavelengths are chosen so that the ratio of fluorescence intensities at the second and third wavelengths is indicative of a carcinomatous condition. Next, the ratio of intensities measured at the second and third wavelengths is determined to obtain a value for each location within the illuminated area. Finally, a map is generated of all the cells present within the illuminated area using the calculated values.