Diabetic nephropathy is one of the main long-term diabetic microangiopathies that can complicate type 1 and 2 and other secondary forms of diabetes mellitus, including posttransplant diabetes mellitus. Posttransplant diabetes mellitus was initially reported in the 1960s, with case reports of recurrent and de novo diabetic nephropathy after kidney transplant reported in the early 2000s, mostly as a result of same-risk and precipitating factors of diabetic nephropathy as in native kidneys. The disease may appear early in view of the hyperfiltration risk of being a single grafted kidney. Here, we discuss risk factors, early serologic and genetic biomarkers for early detection, and strategies to avoid and delay the progression of diabetic nephropathy after posttransplant diabetes mellitus. In this overview of published literatures, we searched PubMed and MEDLINE for all articles published in English language between January 1994 and July 2018. Included studies reported on the prevalence, incidence, or determinants of post-transplant diabetes among renal transplant recipients and studies reporting diabetic nephropathy in their cohorts. Our review showed that avoidance or good control of posttransplant diabetes is the cornerstone in management of posttransplant diabetes mellitus and hence diabetic nephropathy. Control and avoidance can be commenced in the preparatory stage before transplant using validated genetic markers that can predict posttransplant diabetes mellitus. The use of well-matched donors with tailored immunosuppression (using less diabetogenic agents and possibly steroid-free regimens) and lifestyle modifications are the best preventative strategies. Tight glycemic control, early introduction of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, and possibly conversion to less diabetogenic regimens can help to delay progression of diabetic nephropathy.