The present study examined the reliability and validity of the Italian translation of the UPPS-P Impulsive Behavior Scale (UPPS-P) in a clinical sample of 268 consecutively admitted psychotherapy patients (43.3% male; mean age = 40.48 (SD = 12.52); 38.8% inpatient). The Italian UPPS-P replicated the internal consistency coefficients of the original UPPS-P (0.84 to 0.92 across the five subscales). Moreover, confirmatory factor analyses evidenced an adequate fit for the a-priori five-factor model of the scale (WLSMV CFA χ2(1642) = 2833.06, p < .001; RMSEA = 0.052, 95% confidence interval = 0.049 to 0.055, p > .10; CFI = .90; TLI = .90). Furthermore, the UPPS-P scales were significantly related to the Barratt Impulsiveness Scale-11 total score (rs = 0.23 to 0.60 across the five scales). Finally, the five UPPS-P scales showed distinct associations with domain scores and interview-based dimensional scores of personality disorders. These findings suggest that the Italian version of the UPPS-P can be considered a valid and reliable alternative to the original UPPS-P and can be a useful diagnostic tool in a clinical sample.