A concealed toilet comprises a flexible container positioned in a cavity in a vehicle seat. A foundation member attached to the flexible container secures the flexible container to a floor pan of the vehicle via a support assembly. The support assembly comprises externally threaded rods, each having a first end rotatably inserted into an internally threaded L-type adjustment fitting for moving the foundation member between first and second positions along the externally threaded rod, and a second end configured as a spherical bearing stud. An internally threaded lock screw and jam nut arrangement restrains angular movement of the foundation member. Mounting flanges fixedly attached to the floor pan of the vehicle comprise a socket for accommodating the spherical bearing stud. A primary toilet seat member is detachably attached to the foundation member and lock hook assemblies are fixedly attached to opposing sides of the foundation member.