Background Post-transplant diabetes mellitus (PTDM) beyond 12 months (late PTDM) is a severe complication after renal transplantation. Late PTDM develops mostly in subjects with prediabetes. Although exercise may have a potential role in preventing late PTDM, there is no previous data on the effect of exercise in patients with prediabetes. Material and methods we designed a 12-month exploratory study to test the capacity of exercise in reverting prediabetes in order to prevent late-PTDM. The outcome was the reversibility of prediabetes, assessed every 3 months with an oral glucose tolerance test (OGTT). The protocol included an incremental plan of aerobic and/or strength training as well as an active plan for promoting adherence (telephone calls, digital technology, and visits). Results the study included 27 prediabetic patients and was early interrupted due to efficacy. At the end of follow-up, 16 (60%) patients reverted to normal glucose levels at fasting and at 120 min after the OGTTs, two time higher than the 25–30% reversibility rate shown in a previous publication, p value