The basic principles of computerized adaptive testing are relatively straightforward. The practice of implementing and maintaining an adaptive testing program, however, is far more complex. A number of practical challenges await measurement professionals; we discuss four general types: establishing and maintaining item pools, choosing test administration procedures, protecting test security, and responding to examinee issues. The success of an adaptive testing program will largely depend on how well the measurement practitioner deals with these challenges. Key words: computerized adaptive testing, adaptive testing program.