A pet carrier assembly, including: an upper cage housing; and a lower litter pan coupled to the upper cage housing; wherein the lower litter pan is detachable from the upper cage housing and includes a removable waste grate disposed in a bottom portion thereof. The upper cage housing includes a hinged door structure operable for providing access to an interior portion of the upper cage housing. The upper cage housing includes one or more window grates or arrays of holes operable for providing ventilation to an interior portion of the upper cage housing. The pet carrier assembly also includes one or more coupling mechanisms for coupling the lower litter pan to the upper cage housing. Optionally, the pet carrier assembly further includes a moisture absorbent material disposed between the removable waste grate and a bottom of the lower litter pan.