Ig light chain-associated amyloidosis is a fatal plasma cell proliferative disorder that is characterized by fibril deposition in various organs. High-dose melphalan followed by autologous stem cell transplantation has been shown to improve organ dysfunction and survival. This study was undertaken to investigate factors that influence renal response. Patients who had AL amyloidosis with > or =1 g/d proteinuria and a minimum follow-up of 12 mo were recruited. Renal response was defined by >50% reduction in proteinuria with <25% decline in renal function. Hematologic response was defined as a 50% reduction in serum monoclonal protein or free light chains. Baseline characteristics were examined for relationship to renal response. Thirteen of the 135 patients were excluded for various reasons. Median follow-up was 45.4 mo. Hematologic and renal response was noted in 73 and 43.4% of the patients, respectively. Median response time for the kidney was 10 mo (1 to 40 mo). In univariate analysis, low cardiac troponin T (cTnT), higher albumin, lower proteinuria, and hematologic response were associated with renal response. In multivariate analysis, cTnT and proteinuria were predictive of renal response. Renal response was associated with a longer survival than hematologic response alone. This study showed that severe proteinuria and high cTnT negatively affected renal response after autologous stem cell transplantation. Achievement of renal response was associated with improved survival. These results suggest that early intervention with aggressive therapy is not only justified but recommended to achieve optimal response.