The process evaluation of a drug court found clear evidence that the program as implemented complies with benchmarks identified in the literature as "best practices" for drug court operations. The benchmarks include the use of empirically validated and theoretically driven treatment models, ongoing judicial interaction with each drug court participant through regular status hearings, ongoing assessments of treatment services, internal evaluations of drug-court staff regarding service delivery as well as external evaluations of program process and outcomes, the use of a compliance officer to reward cooperation and respond effectively to noncompliance, drug testing, and the use of a collaborative rather than an adversarial processing of cases. Multiple methods were used in assessing the implementation of the drug court. These included face-to-face interviews with all key program personnel, a focus group interview of drug court clients, observations of drug court proceedings, a review of existing county drug court documents, and the collection of archival data from client files. One of the lessons learned is that conducting comprehensive presite interviews helps in establishing the credibility of the researchers with program administrators. A second lesson learned is that researchers should not only compare program implementation with benchmarks in the literature, but also those set by the drug court being studied. Other lessons are that researchers should inform program administrators about the nature of the evaluation process and that researchers should be open to changing research plans once in the field. 1 table, appended presite interview, and 22 references