An epi-illumination system for an array microscope. For Kohler illumination, illumination light sources are placed, actually or virtually, at the pupils of respective individual microscope elements of an array microscope. In one Kohler illumination embodiment, the light source is a point source comprising the tip of an optical fiber placed on the optical axis at the pupil of its corresponding microscope element. In another Kohler illumination embodiment, the illumination light is provided by a reflective boundary placed on the optical axis of a corresponding microscope element. For critical illumination the light sources are placed at locations conjugate with their respective object planes so as to image the light sources thereon. For dark-field illumination, the support material around a microscope element lens, which is used to support an array of lenses, is fashioned to form an illumination optical element so that light from an off-axis source is directed by the illumination element toward the object plane at an angle such that light will not be reflected into the field of view of the imaging system, but scattered or fluorescence light will be within that field of view. The illumination optical element may be refractive element, a Fresnel element, a reflective element, a diffractive element, or some combination of one or more of these elements. An array of pinhole apertures may be provided to operate the array microscope in a confocal mode. All of the embodiments may be used for epi-fluorescence microscopy.