We retrospectively reviewed the impact of impaired renal function (eGFR < 45 ml/min/SA) on post-transplant outcomes in patients receiving ASCT for AL amyloidosis. Patients were grouped into two cohorts, those with normal renal function (NRF) eGFR ≥ 45 ml/min (n = 568) and those with impaired renal function (IRF) eGFR < 45 ml/min (n = 87). Patients with IRF had higher renal stage (>Stage 1: 100% IRF vs 37% NRF, p < 0.0001) and the majority received conditioning with melphalan <200 mg/m2 (70% IRF vs 21% NRF, p < 0.0001). Forty-four patients (6.7%) required dialysis within 100 days of ASCT. Renal stage predicted for dialysis institution within 100 days of ASCT (3% Stage I vs 10% Stage II vs 22% Stage III, p < 0.0001). Dialysis within 100 days was higher in the IRF cohort (16% for IRF cohort vs 6% for NRF cohort, p = 0.0007. Patients with impaired renal function were more likely to be admitted to hospital (80% IRF vs 70% NRF, p = 0.03). The 100-day mortality was higher in the IRF cohort (14% IRF cohort vs 5% NRF cohort, p = 0.008). Median OS and PFS were similar between the two cohorts. Impaired renal function predicts for a higher rate of hospitalization, progression to dialysis and early mortality in patients receiving ASCT for AL amyloidosis.