Background: Census 2011 estimated that there are approximately 253 million adolescents in India, constituting about 20.9% of the total population. Adolescence is an important stage of growth and development in the lifespan. Adolescent is a tender stage which is not only marked by rapid physical growth, but also accompanied by sexual and hormonal turbulence. Inadequate nutrition not only hamper the physical growth but also delay pubertal changes in the body. Methods: This cross sectional study was conducted in the field area of an urban health center, Rohtak, Harayna during the months of January to March 2015. The participants involved were school going adolescent boys 10 to 19 years). The participants were classified as thinness as their under-nutritional status depending upon the Z-score value (WHO growth standards, 2007) of their respective BMI. Results: A total of 649 boy participated in study. Overall mean age of study participants was 15.5 years. The proportion of adolescents who were undernourished based on BMI Z Score came out as 36.7% (13.3% severely undernourished and 23.4% moderately undernourished). Mothers education status was found to have a significant impact on nutritional status of adolescent (P = 0.017). Conclusion: Nutritional status of the studied children is not impressive among adolescent boys, there is a need for health promotion activities in school children by providing an enabling environment and improving nutritional status of the adolescents will go a long way in maintaining the health of the country..