The purpose of this study was to develop a comprehensive career interest inventory based on Super's (1980, 1984) Life Span, Life Space Theory of Career Development, and McDaniels' (1983) concept of Career = Work + Leisure (C = W + L). Career counselors increasingly have recognized the importance of a developmental perspective (Seligman, 1980; Super, 1983) and the inclusion of leisure as an integral component of one's career (Blocher & Siegal, 1984; Edwards, 1984; McDaniels, 1984). The results of this study produced a one hundred and twenty item interest inventory which can be used in career counseling, leisure counseling, or in a holistic approach. The Career Exploration Inventory (CEI) is an innovative instrument which measures developmental work and leisure interests from the past, in the present, and those anticipated in the future. The instrument is a self-administered, scored, and interpreted interest inventory for guided career exploration. Norms were developed for the CEI using two separate norm groups: unemployed/underemployed adults (N=104) and employed adults (N=106) ranging in age from eighteen to seventy-three. Validity of the CEI was comparable to existing work and leisure interest inventories. Coefficient alpha internal consistency measures ranged from .56 to .84, while subjects' top scores for the interest categories were consistent with their work and leisure activities 43 to 51 % of the time. The CEI correctly identified sustained, developmental interests for work (54%) and leisure (67%). Test-retest reliability measures for the eEl ranged from .80 to .92 over a three month period of time. The results of this study verified the utility of a developmental instrument which measures an individual's work and leisure interests over time. Many subjects reported the instrument's accuracy in measuring "true" continuing interests, rather than just current interests. / Ed. D.