Allogeneic hematopoietic cell transplant (HCT) recipients frequently need red blood cell transfusions, and can be at risk for developing iron overload. We studied the prevalence of iron overload in 56 adult allogeneic HCT patients who had survived for a median of 28 (range: 12-151) months from transplant. Patients were initially screened with serum ferritin, and those with serum ferritin >1000 ng/mL underwent R2 magnetic resonance imaging (MRI) of the liver, a sensitive and specific noninvasive imaging technique to measure liver iron concentration (LIC). Iron overload was defined as LIC above normal (>1.8 mg/g dry weight). Nineteen patients had serum ferritin >1000 ng/mL with a median LIC of 7.0 (range: 1.8-28.3) mg/g. The overall prevalence of iron overload was 32% (95% confidence intervals, 20%-46%). The LIC on MRI was moderately correlated with serum ferritin (ρ = .47). Iron overload is a frequent complication of allogeneic transplantation. serum ferritin is a good screening test but does not reliably predict tissue iron overload, and estimation of LIC should be considered before initiating therapy. More studies are needed to determine the impact of iron overload on long-term morbidity and mortality in allogeneic transplant survivors.