Objective: The study sought to dotermine the proportion of patients treated in a jail psychiatric service who were jailed again within a year of release and to identify the factors that most effectively predicted jail recidivism in this population. Methods: Clinical records for a random sample of231 persons who received treatment at a jail psychiatric service were reviewed. Logistic regression analysis of 160 cases not transferred from jail to the state prison was used to identify factors, including demographic and clinical variables and prior jail detention, that predicted reincarceration within a year of release from jail. Results: Younger age, a history of substance abuse, and prior jail detention were strong predictors of jail reincarceration. Conclusions: Return to jail is more likely for a subgroup of jail detainees for whom appropriate, effective treatment is less available in the community. Further research is needed to investigate the relationship between the course of substance abuse and jail reincarceration among younger psychiatric patients. innovative treatments might be used to engage patients while in jail and follow them into the community after release.