Drug courts routinely rely on the threat of legal sanction to motivate drug-using criminal offenders to enter and complete community-based treatment programs. In light of the high failure rates among drug court participants, what is the effect of the threat of legal sanction on program retention and completion? A quasiexperimental research design was used to study program retention and completion within two adult drug courts that employed the same staff to administer identical treatment and supervision programs in the same jurisdiction. One court relied on a 120-day suspended sentence to coerce program participation, whereas the other court was prohibited by law from imposing a jail sentence on its participants. Using alternative measures of program retention, a single measure of program completion, and controls for salient sociodemographic and criminal history factors, the analysis found no differences in program retention or completion between the two courts. (Contains 3 tables and 1 figure.)