The invention relates to an illuminating device for microscopes, wherein the light source has, in particular, a white light illumination having total daylight spectrum and/or an excitation light source for fluorescent colors. The inventive illuminating device for a microscope consists of surface or spatially arranged light sources, which are connected to a control unit for generating any desired illuminating patterns and illuminating spectrums, and an illuminating optic to image these illuminating patterns on the object to be examined. The light sources consist of LEDs (11) which excite at least one luminescence color (14) which is adapted to the wavelength which is emitted by the LEDs (11). The LEDs (11) are arranged concentrically to the optical axis of the illuminating device, preferably, in or in the vicinity of the aperture diaphragm plane. The microscope illumination enables realization of flexible illumination structures and illumination spectrums for bright field, dark field, fluorescence, inclined and/or annularly-shaped illumination, and also white light illuminations having total daylight spectrum. Due to the advantages of the LEDs (economical, low power consumption, long service life and easy to control), such illumination devices are particularly suitable for use in the field, for example, in archaeology, geology and in protecting the environment.