The maximum weight capacity of the Burley pet trailer is 75 pounds. However, you should check your pet’s dimensions and not just the weight. The internal dimensions of the trailer are 18″ x 32.5″. Be sure to check the height, width and length of the trailer compared to your pet. If you have concerns about whether your pet will fit, use masking tape or newspaper on the floor to create a rectangle equal to the length and width of the pet stroller. This will give you an idea of how your pet may fit when he or she is sitting or lying down. In a pet stroller, your pet doesn’t need room to run around, but your cat or dog must be able to sit, stand, turn around, and curl up comfortably.