Estimates of reliability and validity coefficients for the Gray-Wheelwrights Jungian Types Survey (GW/JTS), which was developed to measure Carl Jung's theory of types, are reported in this article. The GW/JTS is an 81-item forced-choice instrument with three bipolar scales, introversion-extraversion (IE), sensation-intuition (SU), and thinking-feeling (TF). Four methods, the GW/JTS, the Myers-Briggs Type Indicator (MBTI), and self- and peer-rating were used to measure IE, SU, and TF in a sample of 187 adults. Reliability coefficients for the GW/JTS scales were .72 for IE, .70 for SU, and .38 for TF; the reliability for TF was not sufficient. Using confirmatory factor analysis and the Campbell and Fiske guidelines, the IE and SU scales demonstrated reasonable construct validity and the TF scale showed limited validity.