A Computer Anxiety Index (CAIN), which uses a six-point Likert scale of agreement, was developed to measure the trait of computer anxiety and to be predictive of the development of the state of computer anxiety. Computer anxiety was defined as the irrational fear or apprehension felt by an individual when using computers or when considering the possibility of computer utilization. College students enrolled in an undergraduate instructional media class at Iowa State University were used to gather validity and reliability measurements. A four-step validation process involved administering the CAIN to subjects two weeks before a scheduled computer lab, administering the State-Trait Anxiety Index as a concurrent measure of computer anxiety, observing subjects while they were using computers, and comparing results of the computer anxiety measures. Normative data were also gathered from computer professionals, other computer users, educators, junior high school and college students, and other adults. The CAIN was found to be reliable and valid, with practical applications in computer anxiety research, career planning, and identification of computer-anxious individuals. (LMM)