BACKGROUND: Despite their great potential to inform intervention planning, screening instruments that assess children's exposure to multiple, non-behavioural risk factors are rare. The Family Risk Factor Checklist-Parent (FRFC-P), was designed to facilitate community risk factor profiling and subsequent intervention planning. The aims of the current study were to establish the psychometric properties of the FRFC-P and to examine the relative importance of family risk factors in relation to the onset versus persistence of children's mental health problems. METHOD: Data were collected from 1022 parents of 4-8-year-old children as part of the Promoting Adjustment in Schools Project (PROMAS). The FRFC-P assessed children's exposure to risk across five domains: adverse life events and instability (ALI); family structure and SES (SES); parenting practices (PAR); parental verbal conflict and mood problems (VCM); and parental antisocial and psychotic behaviour (APB). RESULTS: The FRFC-P had satisfactory test-retest reliability and construct validity, but modest internal consistency. Risk assessed by the PAR domain was the most important determinant of mental health problem onset, while the PAR, VCM, and APB domains were the strongest predictors of mental health problem persistence. CONCLUSIONS: These findings highlight the importance of considering risk factors for onset separately from risk factors for persistence of mental health problems and indicate that the studied population may benefit the most from preventive interventions that address parenting practices and treatment interventions that address parenting practices, and parental mood problems, conflict, antisocial behaviour, and psychiatric disorders.