The objective of this study was to evaluate zonal and state-wise prevalence and risk factors of undernutrition among Indian men in the age-group of 15 to 54 years based on sampled data of 74,369 respondents from the National Family Health Survey-3. A common anthropometric measure, body mass index, is used to determine the prevalence as it is considered to be a good measure of undernutrition. Overall, 28.6% (SE = 0.17%) of Indian men are classified as underweight, and 52.5% (SE = 0.62%) of the younger age-group (15-19 years) are underweight. The highest prevalence of underweight men in Indian states is observed in Tripura (39.8%; SE = 1.85%), followed by Rajasthan (39.3%; SE = 1.28%), Chhattisgarh (37.2%; SE = 1.3%), and Gujarat (35.7%; SE = 1.3%). The highest and lowest prevalence among zones are reported for central (34.5%; SE = 0.39%) and northeast (18%; SE = 0.34%) zones, respectively. The bivariate analysis using chi-square test concludes the significant association (p < .001) between the body mass index groups and each of the explanatory variable. Significant difference (p ≤ .002) is reported in the mean heights of underweight and non–underweight men among four out of six zones of India. From multivariate logistic regression analysis, we observed that for India as a whole, men with no education, low/medium standard of living, and the younger age-group (15-19 years) have significantly (p < .001) higher chances of being underweight. We also observed similar results for many Indian states at different significance levels. In conclusion, the distribution of underweight in India remains segregated by socioeconomic status.