The purpose of this research was twofold to describe the types of drugs and alcohol abused by pregnant multisubstance abusers enrolled in a substance abuse and treatment programme, and to describe the types of changes in drug-taking behaviours during pregnancy An exploratory study, including interviews and chart reviews, was conducted with 31 pregnant multisubstance abusers Drug-taking behaviours, demographic factors of age, ethnicity, marital status, education, and pregnancy characteristics of gravida, living children, level of prenatal care and trimester of pregnancy were measured Most of the women were in their twenties, Hispanic, single, and had some high school education Most of the women were multiparas to grand multiparas, yet they had only one or two living children, and all were receiving prenatal care Their self-reports were validated by urine screening Generally, the women reported that they did change their drug-taking behaviours, and many women decreased their substance abuse