A protective undergarment (10), shown in the form of shorts, includes integrally formed protective panels (22, 26, 30) that exhibit slash-proof properties. The protective areas (22, 26, 30) are made from a flexible Kevlar® knit or the like, and extend to cover the groin, crotch, substantial areas of the buttocks and the inner thigh regions of both legs. The protective panels (22, 26, 30) are externally snitched to a low thermal burden material (18, 20), such as a polyester mesh, that provides elasticity and completes the structure of the shorts (10). The Kevlar® knit is flexible and preferably lies directly against the skin of a user to provide blast wave and ballistic fragment deflection while permitting mobility in a lightweight arrangement. Varying thickness of the Kevlar® knit can be used in the protective areas (22, 26, 30) selectively to enhance protection against blast wave and fragment penetration. The shorts (10) find particular application in battlefield theatres where military personnel are exposed to bomb threats.