Stereomicroscope having a main objective (2) and a zoom system (7) provided downstream of the main objective (2), wherein between the objective (2) and the zoom system (7) is provided a first deflector (30) for deflecting viewing beam pencils emanating from the objective (2) into the zoom system, the zoom system (8) comprising substantially horizontally extending magnification and viewing channels (7a to 7d), wherein the first deflector (30) is of semitransparent construction, while a first illuminating device (50; 60, 65) is provided for illuminating an object that is to be viewed through the first deflector 30 and the main objective 2.