Objective:: To investigate the unique contribution of narcissism and impulsivity, in addition to callous-unemotional (CU) traits, in explaining concurrent prosocial and antisocial behavior. Method:: Two hundred and forty-nine schoolchildren (53% female; age 9-12 years) completed the self-report Strengths and Difficulties Questionnaire (SDQ) and the Antisocial Process Screening Device (APSD). Two statistical models were tested, predicting conduct problems (CP) and prosocial behavior (PB). In the first one, CU traits and gender were entered into the equation. The second model added narcissism and impulsivity. Results:: Gender, narcissism and impulsivity, but not CU, were statistically significant predictors of CP in the second model (F3,226 = 45.07, p < 0.001, R2 = 43.7%; betas: gender = -0.20, narcissism = 0.29, impulsivity = 0.36, CU = 0.06). PB was significantly predicted by all domains except gender (F3,226 = 42.57, p < 0.001, R2 = 42.4%; betas: gender = 0.08, narcissism = -0.16, impulsivity = -0.23, CU = -0.41). Conclusion:: Our results confirmed that CU traits refer to a distinct manifestation of psychopathy in youth, but we also found that narcissism and impulsivity are equally important when predicting CP. Previous reports of sex differences on APSD and SDQ domains were also corroborated.