BACKGROUND Initially described as a relatively benign condition, recent studies report graft loss in up to 50% of the patients with post-transplant IgA nephropathy. There is no evidence for the best therapeutic approach, and prognostic factors remain to be elucidated. MATERIAL AND METHODS Single center retrospective analysis of patients >12 years old, with clinically relevant post-transplant IgA nephropathy (proteinuria ≥1.0 g/g and/or graft dysfunction) and ≥6 months follow-up after diagnosis (n=47). RESULTS Living donor transplants represented 85% of cases. Dysmorphic hematuria (100%), blood pressure elevation (95.7%), renal dysfunction (70.2%) and subnephrotic proteinuria (60.6%) predominated at presentation. Using the Oxford Classification, mesangial proliferation was the main histological lesion (91%). Treatment consisted mostly of blockade of the renin angiotensin system (89.4%) and modification of immunosuppression (85.1%), mainly by increasing oral steroids dose (83%), with venous pulse therapy in 63.8% of cases. Partial and complete remission occurred in 48.9% and 17% of cases, respectively. One patient died (sepsis) and 15 patients (31.9%) lost their grafts due to nephropathy. The percentage of decrease in glomerular filtration rate at diagnosis was independently associated with partial remission (HR 0.97, 95% CI 0.94-0.99, p=0.01) and graft loss (HR 1.13, 95% CI 1.06-1.20, p<0.001). Deceased donor (HR 28.04, 95% CI 4.41-178.39, p<0.001) and donor age (HR 1.1, 95% CI 1.04-1.16, p=0.001) were also risk factors for graft loss. CONCLUSIONS Despite treatment, most patients with post-transplant IgA nephropathy in this cohort study presented unfavorable outcomes, and graft dysfunction at diagnosis appeared to be the main prognostic marker.