The present study examined the predictive validity of certain tests of mechanical ingenuity as well as the concurrent validity of various measures of interests, backgrounds, and personality dimensions thought to be related to scientific creativity. The Ss (total N=528) used for this purpose were a group of engineers who had been enrolled in mechanical engineering curricula at the time of testing, but were currently engaged in research, design, or development. Predictive validities of .23 to .35 were obtained with a content relevant ability measure against a weighted composite criterion made up of patents, publications, etc.; but when scores from this test were placed in a regression equation along with concurrently validated scales from a life history questionnaire, the correlation between the regression scores and the criterion ranged from .41 to .69. The factorial scales that made the major contributions to this prediction were designated as drive, independence, research orientation, and positive home and educational background. These findings along with a skewness of the criterion scores supported the authors' general position that a creative act is not a function of a single trait or ability, but is a phenomenon (or an event) that is probably based on a series of relatively independent types of variables.