This paper presents three studies on Larson's 1996 Driver's Stress Profile, a measure of aggressive driving tendencies. In Study 1, utilizing 33 individuals (15 men, 18 women) who took the test twice with one week between tests, we found the test to have good test-retest reliability ( r = .93). In Study 2, utilizing 176 individuals (77 men, 99 women), we found different preliminary norms for men and women and good internal consistency (.93). We also found significant correlation between the total test scores and age ( r = −.27) and a significant correlation (age corrected) between total test scores and number of self-reported MVAs ( r = .28). An exploratory factor analysis indicated that three factors, including 28 of the 40 items, accounted for 43.4% of the variance. In Study 3, utilizing the same subjects as in Study 2 (84 individuals from the community of average age 35.3 yr.; 92 college students of average age 18.9 yr.), we found the full scale scores correlated significantly with scores on Trait Anger and Anger Out and Type A Behavior, especially speed and impatience. Finally, scores correlated significantly with the Deffenbacher Driving Anger Scale ( r = .57) but clearly tapped processes different, in part, from those measured by the Deffenbacher, et al. scale (1994). Overall, the Driver's Stress Profile appears to be a sound, reliable, and valid scale for use with aggressive driving.