Adolescence explained as a period of age between 10 to 19 years. This is a major contributing period to build up the health of girls. Ferritin is an intracellular protein that contains iron and releases it in a controlled fashion and it reflects body iron stores and systemic inflammation during adolescent period. It is considered the best single test for the diagnosis of iron deficiency anemia during adolescent because its concentration is directly proportional to total body iron stores in adolescent period. This study was done in the Department of Physiology, Mymensingh Medical College, Mymensingh, Bangladesh to evaluate the changes of serum ferritin levels among iron deficient anemic adolescent girls in comparison to healthy adolescent girls in Bangladesh. This was a cross sectional, prospective, analytical type of study. This study ranged from 10-19 years of adolescent girls. Seventy (70) healthy adolescent girls, as control group (Group I). Seventy (70) iron deficiency anemic adolescent girls as study group (Group II). Serum ferritin was estimated by Micro-particle Enzyme Immunoassay Test Kit. Data were expressed as mean (±SD). Statistical significance of difference among the Group I and Group II were calculated by unpaired students 't' test. The mean±SD level of serum ferritin among Group I and Group II were 26.22±4.03μg/L and 13.33±3.18μg/L respectively. Mean values ±SD of serum ferritin significantly lower in (Group II) in comparison with (Group I). Higher numbers of adolescent girls are still suffering from anemia along with low level of serum ferritin in Bangladesh. For combat this situation, immediate, sustainable and long term public health intervention and nutritional supplementation must be required.