An illumination device includes at least four semiconductor radiation sources (18) for emitting optical radiation in respectively different emission wavelength ranges. At least one color splitter (22.1, 22.2, 22.3), which is reflective for optical radiation of the respective semiconductor radiation source (18), is assigned to each of at least three of the semiconductor radiation sources (18). The semiconductor radiation sources (18) and the color splitters (22.1, 22.2, 22.3) are arranged such that the optical radiation, which is emitted in each case from each of the semiconductor radiation sources (18), is coupled into a common illumination beam path section (24). In each case, one collimating unit (20.1, 20.2, 20.3, 20.4), which collimates the optical radiation emitted by the respective semiconductor radiation source (18), is arranged in the beam path sections from the semiconductor radiation sources (18) to the color splitters (22.1, 22.2, 22.3).