A cage (10) for rabbits or similar pets comprising a grill element (11) generally having a rectangular shape and which can be curved or shaped at the top as required, and where the grill element is applied to the top edge of a basin-shaped tray with modular walls and where this base comprises a bottom surface (13) and side walls (14, 15) which respectively form the long sides and the short sides of the tray, where the cage can be joined to at least one further cage alongside, where the cages are joined by removing from each of the cages their respective vertical wall (15) on the joining side, preferably the short side but also the long side, and where the two trays are held together by a specially shaped horizontal profile (18) with an up-turned “U” shape comprising the two vertical sides (19) which overlap on the joined edges of the tray bottoms positioned side by side.