A universal microscope condenser includes a supporting member having a fixed lens mounted thereon. A pivot arm is pivoted to the supporting member and a first lens member mounted on the pivot arm for movement by the pivot arm into optical alignment with the fixed lens. The supporting member also includes a carrier slide which has a second lens member mounted thereon. The first and second lens members can be switched in and out of optical alignment with the fixed lens to vary the aperture and luminous field of the universal microscope condenser. Also included is a variable aperture stop disposed between the first and second lens members. Preferably, the first lens member moves along an arcuate path which intersects the optical axis of the fixed lens and the second lens member moves along a path which is tangent to the arcuate path of the first lens member when the first lens member is aligned with the optical axis of the fixed lens.