ABSTRACT: Background:Prenatal smoking rates vary substantially among racial and ethnic groups. Although prevalence of smoking among Aboriginal people in Canada is higher than in the general population, little is known about smoking rates during pregnancy among Aboriginal women or the characteristics of Aboriginal women more likely to smoke during pregnancy. The study purpose was to describe and compare the prevalence and correlates of smoking during pregnancy among Aboriginal and non-Aboriginal women giving birth in the Canadian province of Manitoba. Methods:Data were obtained from interviews with 684 postpartum women who delivered a live singleton infant in two tertiary hospitals in Manitoba. Stratified analysis was used to describe effect-measure modification for correlates of smoking among the Aboriginal and non-Aboriginal groups. A multivariable logistic regression was conducted for the total sample. Results:A significantly higher proportion of Aboriginal women (61.2%) than non-Aboriginal women (26.2%) smoked during pregnancy. No correlates of smoking during pregnancy were specific to Aboriginal women, but several maternal characteristics were associated with smoking among non-Aboriginal women. After controlling for other factors, significant correlates of smoking during pregnancy for the total sample included inadequate prenatal care, low support from others, single marital status, illicit drug use, Aboriginal race/ethnicity, and noncompletion of high school among non-Aboriginal women. Conclusions:The high prevalence of smoking during pregnancy, particularly among Aboriginal women, necessitates coordinated efforts aimed at smoking prevention and cessation. (BIRTH 32:4 December 2005)