Objective We explored the association of smoking and GBS colonization among women delivering neonates 35 weeks+. Design Retrospective chart review Setting A large tertiary care inner-city hospital in the southern United States Population/Sample 803 women pregnant women of term or near term neonates Methods The electronic health records of a convenience sample. Main Outcome Measures The outcome variable of interest was maternal GBS colonization. The primary independent variable of interest was tobacco smoking during pregnancy. Results The prevalence of maternal GBS colonization was 32% among the study population. In the univariate analyses, factors associated with maternal GBS colonization were tobacco smoking during pregnancy (P of trend <0.001), Race (African Americans with the highest colonization rates and East Asians the lowest; P<0.001), maternal age <20 years (P=0.006), low birthweight <2500 gm (P=0.02), maternal drug use (P=004), and gestational age <37 (P=0.041). Gestational diabetes, parity, and gender were not predictive of GBS colonization. In the multiple logistic regression analysis, Women who smoked during pregnancy were more than twice more likely to be colonized than their non-smoking counterparts (OR=2.6; 95% CI=1.5- 4.6; p<0.001). Maternal age was the only other significant predictor with young mothers < 20 years more than one and a half time more likely to be colonized than their older counterparts (OR= 1.65; 95% CI=1.02-2.68; P=0.04). Conclusion Smoking during pregnancy was identified as an independent risk factor for GBS colonization. This is another reason that women should refrain from smoking during pregnancy to avoid risking their babies developing GBS disease.