Abstract: A modular easily assembled cabinet system includes components in kit form including generally rectangular base, top, side and back members, and four elongated corner post or upright members. The corner post members each define an external longitudinal corner and internally facing longitudinal channels. The opposite ends of each post member define connector ends having transverse recesses adapted to receive tongue portions of connector sites formed on each corner of the base and top members. During assembly, vertical lateral edges of the side members are received within channels in the corner posts, and upper and lower edges are inserted into channels formed in the base and top members. Fasteners releasably secure the connector site tongues within the corner post recesses. A door may be hinged between the base and top members. The base, top and door may be formed of blow molded plastic, with the base and top members being configured to enable nesting of cabinets in vertically stacked relation.