© Mary Ann Liebert, Inc. 2015. Background: We examined factors associated with women's use of highly effective birth control before and after incarceration, since women with ongoing criminal justice involvement bear a disproportionate burden of sexual and reproductive health problems, including high rates of unintended pregnancy and inconsistent contraceptive use. Methods: Using a longitudinal study design, we conducted surveys with 102 women in an urban midwestern jail and then followed up with 66 of them 6 months after incarceration. We used stepwise logistic regression to assess individual, interpersonal, resource-based, organizational, and environmental factors associated with utilizing highly effective birth control. Results: Forty-two percent of women reported utilizing highly effective birth control (e.g., sterilization or other highly effective reversible methods) prior to incarceration, and 54% reported using these methods after release from jail (p<0.001). Ninety percent of women reported not wanting to get pregnant. Consistent use of birth control (p=0.001) and alcohol problems (p=0.027) were associated with utilization of highly effective birth control prior to incarceration. Previous pregnancies (p=0.012) were the only factor associated with utilization of highly effective birth control after release from jail. Conclusions: Clinicians and public health practitioners can use findings from this study to develop clinical and intervention efforts aimed at improving unintended-pregnancy prevention among incarcerated women both during their confinement and during the tumultuous period after their release from jail.