Toxic-infectious complications may be related with iron toxicity after a stem cell transplant (SCT). Eighty one patients who underwent SCT were prospectively evaluated over 3 months for mucositis, bacteraemia and febrile days. Pre-SCT transferrin saturation (TS), ferritin level and the number of days with TS ≥ 80% after transplant were determined. A ferritin level >1,500 μg/l predicted the appearance of severe mucositis, bacteraemia and days with fever in univariate (P = 0.03, P = 0.03 and P = 0.03) and multivariate analysis (P = 0.03, P = 0.006 and P = 0.002). Nevertheless, further statistical studies revealed that the predictive value of pre-SCT ferritin levels was restricted to AUTO-transplanted patients in both univariate (P = 0.05, P = 0.05 and P < 0.001) and multivariate (P = 0.03, P = 0.05 and P < 0.001) analysis, in contrast with the ALLO-transplanted group where this variable did not reach statistical significance. In conclusion, iron burden seems to influence the appearance of toxic-infectious complications during the first 3 months after transplant in AUTO-transplanted patients.