The fastest growing component of the prison and jail populations in the United States is offenders who fail while under community supervision. The increased use of multiple conditions of probation raises two enforcement problems for both probation agencies and the judiciary: how probation officers should respond if an offender refuses to comply with the conditions of probation and absconds; and how a judge should respond to noncompliance when and if the offender is subsequently apprehended. This article examines how the Maricopa County, Arizona Probation Department addresses these questions. This department established a warrants unit devoted to the location and apprehension of the absconder. Focusing on the probation office response, the results of a randomized field experiment designed to test the effects of two different strategies for locating and apprehending absconders with this specialized probation-based warrants unit are presented. Results suggest that early identification of absconders by supervising probation officers, combined with proactive offender location and apprehension strategies, may result in higher apprehension levels with no significant change in return to prison/jail rates due to formal revocations. A proactive, probation-based warrants unit appears to be an effective strategy for locating and apprehending offenders who abscond. The article identifies broader issues concerning sentencing practices and judicial responses to technical violators that merit further research. Tables, references, notes