While prevalence of smoking during pregnancy has declined over the past two decades, maintenance of cessation after pregnancy remains an important public health challenge, particularly for women of color. This article reports on methods for improving detection of women at risk for smoking resumption after pregnancy through the use of an evidence-based smoking assessment instrument. The instrument was adapted for use by lay health workers in a community-based maternal and infant health program. A total of 276 primarily low-income Black and Hispanic pregnant and postnatal women enrolled in the program were screened for tobacco use in an initial assessment. Of these, 190 were reassessed an average of 2.7 months later. Assessments included measures of current and past smoking and risk factors associated with relapse. Bivariate differences by smoking status were analyzed. Seventeen percent of participants who would be classified as non-smokers using less sensitive screening questions were identified as former smokers and at-risk for resuming smoking. Twenty-two percent of former smokers resumed smoking by reassessment. Smoking resumption among former smokers was associated with having a partner and household members who smoked. Identification of former smokers is critical in order to prevent resumption of smoking after pregnancy and promote long-term maternal smoking cessation. Brief assessment instruments administered at multiple points in time during the prenatal and postnatal periods are an effective means of improving detection of women at risk for smoking resumption. Former smokers should be included in prenatal and postnatal tobacco education and counseling services.