A general requirement of most biological research laboratories is suitable compact storage space for microscope slides. This is particularly true where space is required for storing deeper preparations such as whole mounts in a horizontal plane with their identification labels in full view. Of the many commercial cabinets now available few appear to be entirely satisfactory. Although some are constructed to hold the slides horizontally, in these the slide holders are in the form of trays with a capacity of not more than one dozen slides and the trays are carried in grooves nne above the other. In others, thin drawers are used in which the slides are laid side bv side on the bottom. In the former, considerable handling is required to expose the labels of the slides. In the latter, slides easily become disarranged, and are exposed to an accumulation of dust; and though considerable space is required, the capacity of the drawers in most cases is limited to less than 100 slides. A cabinet in which a number of desirable features is incorporated has recently been developed at this laboratory, and a description of it constitutes the basis of the present paper.