We measured growth [length (L) standard deviation score (SDS), growth velocity (GV) SDS and body mass index (BMI)] and hematological (hemoglobin, hematocrit, MCV and MCH) parameters in 40 children (aged 17.2 +/- 12.4 months) with iron deficiency anemia (IDA) before and after iron therapy. Before treatment children with IDA had LSDS = -1.2 +/- 1, GV = 7.5 +/- 2.2, GVSDS = -1.42 +/- 0.6 and BMI = 13.5 +/- 1.2. They were significantly shorter and had reduced growth as compared with age-matched controls. After treatment, their growth parameters significantly increased with LSDS = -0.6 +/- -0.9, GV = 13.2 +/- 4.4 cm year(-1), GVSDS = 1.7 +/- 0.5 and BMI = 14.2 +/- 1.1. Their GV correlated significantly with serum ferritin concentration (r = 0.48, p < 0.001) and BMI (r = 0.32, p < 0.1). In summary, IDA during the first 2 years of life significantly impairs growth.