Diarrhea is a common occurrence following vascular organ transplantation, including kidney transplants. It can be induced by non-infectious factors, adverse effects of immunosuppressive drugs, or infectious agents such as viruses, bacteria, fungi, or parasites. Intestinal protozoan parasites, include Cryptosporidium spp., are causes of infectious diarrhea particularly in immunocompromised patients. This review aims to summarize reports on epidemiology, pathogenesis, clinical presentation, diagnosis, and treatment of Cryptosporidium spp. infection in adult patients, particularly following kidney transplantation.