While clinician-administered symptom rating scales are the most commonly used outcome measures in pharmaceutical research, error variance due to poor inter-rater reliability increases the risk of type II errors in multi-center clinical trials. Such error variance could obscure true differences between active drug and placebo, or between two comparator compounds. Computer-administered versions of symptom rating scales originally designed to be administered by trained clinicians offer a solution to this problem. This paper reviews the empirical data on the reliability, validity and equivalence of computer-administered rating scales. Computer-administered versions of clinician-administered scales are now available for the assessment of depression, anxiety, obsessive-compulsive disorder, and social phobia. Validation studies support the reliability, validity and equivalence of these scales. Patient reaction has been positive, with patients generally more honest with and often preferring the computer for assessing sensitive areas such as suicide, alcohol or drug abuse, sexual behavior, or HIV related symptoms. Applications using Interactive Voice Response (IVR) technology facilitate longitudinal monitoring of patients without requiring office visits to collect data, increase the accessibility of information to the clinician, and the quality of patient care through more informed decision making. When used in accordance with established ethical guidelines, computers offer a reliable, inexpensive, accessible, and time-efficient means of assessing psychiatric symptoms.