In order to better evaluate the effects of centrally active drugs, a new computer based set of psychomotor tests was developed. Compared to the older apparati, the new set is very flexible and easy to operate allowing the measurement of hand/eye coordination, attention and several types of reaction skills. To evaluate the sensitivity and usefulness of the new tests, the effects of alcohol (oral doses of 0.5 g/kg and 1.0 g/kg) were studied in twelve healthy volunteers. The peak blood alcohol concentration after the larger dose was 0.86 g/l, and the effects were clearly seen with all new tests. The smaller dose of alcohol gave 0.33 g 1 peak blood alcohol concentration and it impaired significantly only coordination at 1 hr after drinking. The results suggest that the new tests are at least as sensitive and reliable as older psychomotor tests detecting the effects of central depressant agents. The advantage of the new tests is that they are easy to operate and easy to modify without any specific programming skills. Because they can be used with a computer which is easy to transport, these tests are suitable for use in clinical areas to conduct studies with patients.