This study examined two potentially useful personality scales, the narcissistic personality inventory (NPI) and the self-report of psychopathy scale (SRPII), in terms of their factor structures. Competing factor structures for each scale were assessed via confirmatory factor analysis (n=581). Competing models were obtained from published literature associated with each scale and also through exploratory factor analysis. From the literature, Raskin and Terry (1988) provided a seven factor NPI model, whereas Emmons (1984; 1987) suggests a four factor model. Harpur and Hare (personal communication) provided a two factor model for the experimental SRPII. Exploratory factor analysis (n=581) provided four additional NPI models and five additional SRPI models to test. Various additional factor models of interest were included in the competing models pool. The published seven factor Raskin and Terry (1988) model of the NPI, the proposed two factor Harpur and Hare SRPII model, and the seven factor oblique exploratory SRPI model fit the data best in terms of common fit measures. Theoretical implications of model fit are discussed and consideration is given to this study as a method of practical scale analysis and theoretical construct validation.