We provide the first validation data on the Spanish version of the Brief Problem Monitor-Parent form (BPM-P), a recently developed abbreviated version of the 120-item Child Behavior Checklist for Ages 6 to 18 (CBCL/6–18) in young schoolchildren. Parents of a community sample of 521 children aged 6–8 answered the CBCL/6–18 yearly, and the 19 BPM-P items were examined; parents also provided different measures of psychopathology. Confirmatory factor analysis of the expected 3-factor model (attention, externalizing, and internalizing) showed adequate fit (root mean square error of approximation, RMSEA ≤ .057), and measurement invariance across sex and age was observed. Internal consistency for the derived scores was satisfactory (ω ≥ .83). Concurrent validity with the equivalent scale scores of the original full CBCL/6–18 (r ≥ .84) and convergent validity with parents’ ratings of the Strengths and Difficulties Questionnaire scores (r ≥ .52) were good. BPM-P scores at age 7 showed good predictive accuracy for discriminating the use of mental health services (OR ≥ 1.12), functional impairment (B ≤ −1.25), and the presence of the corresponding disorders diagnosed with an independent clinical interview, both cross-sectionally at age 7 and longitudinally at age 8 (OR ≥ 1.24). The BPM-P provides reliable and valid scores as a very brief follow-up and screening tool for assessing behavioral and emotional problems in young schoolchildren.