We examined the trends and determinants of second-pregnancy smoking behavior among Michigan young-adult mothers who smoked during their first pregnancy (N = 14,731). Maternally linked Michigan birth certificate data (1989-2004) were used to identify first and second pregnancies for young-adult mothers. ZIP code data were merged with census data to proxy for median household income and population size at the ZIP code level. For first-pregnancy smokers, linear and logistic regressions were used to analyze (a) the determinants of second-pregnancy smoking and (b) the association of birth outcomes with second-pregnancy smoking. Among young adults who smoked during their first pregnancy, second-pregnancy smoking was (a) inversely related to income and population, (b) less prevalent after 1997, (c) more likely after a low-birthweight first birth, and (d) less likely after a premature first birth. Despite recent declines in second-pregnancy smoking rates among young adults who smoked during their first pregnancy, these rates remain disturbingly high (more than 70%). Future smoking cessation efforts should target mothers who have lower incomes, live in less-populated areas, and have previously had low-birthweight babies. The results suggest that higher cigarettes taxes would also further reduce recurrent smoking.