Microcomputer playfulness represents the degree of cognitive spontaneity in microcomputer interactions. Research on the general characteristic of playfulness has demonstrated relationships with measures such as creativity and exploration. Thus, with the widespread diffusion of computers in organizations, research in micro-computer playfulness can have significant practical implications for organizations. Five independent studies involving more than 400 participants provided initial evidence for the construct validity of a microcomputer playfulness measure with respect to its factor structure, internal consistency reliability, concurrent validity, discriminant validity, predictive validity, predictive efficacy, and test-retest reliability. As hypothesized, the measure related positively to computer attitudes, anxiety, competence, and efficacy, and did not relate to gender or age. In addition, the measure related positively to training outcomes of learning, mood, involvement, and satisfaction. Further, the evidence suggests the predictive efficacy of microcomputer playfulness as compared to other variables, such as computer anxiety and attitudes. Consequently, the findings indicate that researchers should focus more attention on positive influences on human-computer interaction, such as microcomputer playfulness, rather than on negative influences, such as computer anxiety.