A modular crypt structure comprising a frame, a module insert defining a chamber and a closure panel and methods of constructing the same are disclosed. The chamber functions as a crypt module and receives bodily remains or portions thereof. The chamber is closed by attaching a closure panel, such as a stone crypt front to the frame. The modular crypt frame may comprise a plurality of horizontal bars and a plurality of vertical bars. A method of constructing a modular crypt structure comprises erecting a frame, providing at least one module insert, configuring the insert to define a chamber adapted to receive bodily remains, and closing the crypt module. A modular crypt system including a niche side wall is also disclosed having a niche side wall frame, a niche insert defining a plurality of niches positioned within the frame, and a closure panel positioned on the niche side wall frame.