Anemia is a major health problem in developing countries like ours’. Although macrocytic anemia constitutes a minor portion among nutritional anemias, Vitamin B12 (Cobalamin) and Folate deficiency in Indian population is quite prevalent. As the of studies evaluating the relationships of these nutritional parameters with RBC indices in the same group of study participants are limited, we planned this study to study correlation of serum Ferritin, Vitamin B12, Folate with and RBC indices. A case-control study including 100 patients with anemia (Cases) and 100 age and sex-matched subjects without anemia (Controls) was conducted at UPUMS, Saifai, Etawah, Uttar Pradesh. Patients satisfying WHO criteria of anemia were included as cases, while those with history of any factors that are known to alter study parameters were excluded. Estimation of all study parameters was done following standard operating procedures of our laboratory and the results were analysed using appropriate statistical methods. In our study, serum Ferritin (p=0.0001), Vitamin B12 (p=0.0004) and Folate (p=0.0001) deficiency were found to be significantly higher in cases, compared to controls. There was a moderate positive significant (p-value<0.05) correlation of Hb with serum Ferritin in both cases and controls. We also observed a positive significant (p-value<0.05) correlation of MCV with serum Ferritin in both groups. There was also a mild negative correlation of MCV with serum Vitamin B12 and Folate, in both groups of cases and controls. Based on our findings, it may be concluded that Microcytic RBCs on microscopic examination does not necessarily mean serum Ferritin deficiency. It could be a concomitant deficiency of both serum Ferritin and Vitamin B12.