Magnitude and severity of iron deficiency was evaluated in 413 randomly selected adolescent school girls (10–15 y) from Tigray, Northern Ethiopia. Mean (sd) hematocrit (hct) and ferritin levels were 42.9 (3.3) % and 48.4 (25.1) μg/L, respectively. Stunting was common (23.5%) and 27.1% were thin (−2Z) on the basis of BMI. Serum transferrin receptors (sTfR) for the 148 girls with lowest ferritins ranged from 4.5 to 20.5 with mean levels of 8.2 (2.6) mg/L. Mean and median (25th, 75th) for hsCRP were 0.99 (2.4) and 0.4 (0.2, 0.8) mg/L, respectively. The prevalence of anemia in the girls was 7.1% after adjusting hct for elevation (1500–2646 m). Fifty seven (16.2%) of the girls were iron depleted (ferritin < 15μg/L) and 13.7% had low iron stores (ferritin 15–30 μg/L) suggesting that iron deficiency was prevalent in this population. Anthropometric indicators including HAZ (r = 0.16) and MUAC (r = 0.16) correlated (p<0.004) with hct. Girls involved in fire wood collection and agricultural activities had significantly lower hct. The most common parasites were E. histolytica (19.9%) and H. nana (8.6%). However, parasites commonly associated with anemia including hookworm (1.8%), S. mansoni (0.6%) and malaria (0.6%) were rare. Anemia was a public health problem in the adolescents and 30% of the girls were at risk of iron deficiency (ferritin < 30 μg/L). Multifactorial causes of anemia in the adolescent girls needs further investigation. (Supported by: NORAD II, Mekelle Univ, Ethiopia & Oklahoma State Univ, USA).