Aim: To investigate the relationship of body mass index (BMI) with systolic (SBP), diastolic (DBP) and mean arterial (MAP) blood pressures among adult male slum dwellers of Kolkata, India. Subjects and methods: A total of 470 adult (18-84 years) male slum dwellers of Bengalee ethnicity residing in Dum Dum, a suburb of Kolkata, India, were investigated. Height, weight and blood pressures (BP) were recorded using standard techniques. The BMI was calculated using the standard equation. Participants were classified into nutritional categories by BMI values following the World Health Organization (2000) guidelines. Hypertension (HT) was determined following JNC-VII criteria. Standard statistical techniques were utilized. Significance was set at p<0.05. Results: Mean (SD) age and BMI of the subjects were 37.5 (14.2) years and 20.3 (3.2) kg/m2. Means (SD) for SBP, DBP and MAP were 121.6 (15.5) mmHg, 79.6 (9.7) mmHg and 93.5 (11.1) mmHg, respectively. Significant (p<0.001) differences were observed for age, weight and BMI between hypertensive and normotensive individuals. For all the parameters, hypertensive individuals had higher means. Age had significant (p<0.001) correlations with SBP, DPB and MAP, but not with BMI. BMI was also significantly (p<0.001) correlated with SBP, DBP and MAP. Significant (p<0.001) partial correlations (after controlling for age) of BMI with SBP, DBP and MAP were also observed. Mean values of SBP, DBP and MAP increased steadily from the undernourished through the normal to the overweight individuals. There were significant differences in the percentage of HT between the nutritional categories. The prevalence of HT was lowest in the lowest BMI categories (undernourished and normal) (16.2 and 15%) and highest in the obese group (43.2%). Multiple regression analyses of BP variables on BMI demonstrated that BMI had significant influence on them, irrespective of age, MPCI, smoking and alcohol intake status. BMI independently explained 5.8%, 11.4% and 10.6% variation in SBP, DBP and MAP, respectively. Among the variables controlled for, age had the strongest significant effect on SBP (Adj R2=0.132), DBP (Adj R2=0.054) and MAP (Adj R 2=0.086). Conclusion: In conclusion, our study demonstrated BMI as an independent risk factor for HT, and overweight status (BMI23 kg/m2) significantly increases its risk among adult Bengalee male slum dwellers of Kolkata. © 2009 Springer-Verlag.