The objective was to determine the relationship of hemoglobin and hematocrit levels with BMI, age and sex in children under 9 years of age from the Centro Poblado el Tropico District of Huanchaco, in September, 2016. Material and Method: The study was descriptive , Cross-sectional and prospective. Participants included 65 children under the age of 09 of both sexes, with prior consent and informed consent before inclusion in the study. Anthropometric measurements were performed using the following variables: weight (Kg) and height (cm), determination of hemoglobin (Hb) by cyanometahemoglobin method and hematocrit (Hto) by microcentrifugation. The determinations were analyzed and compared with BMI, age and sex. RESULTS: The mean values in the children under age were Hb 11.33 ± 2.85 g / dl, hto 39.47 ± 10.49%, BMI 19.61 ± 9.06 and age 7.41 ± 6.29. 7.8% had decreased Hb values and BMI co...