The aims of this study were to explore parenting stress in mothers of at-risk families as a predictor of psychological symptoms and to examine moderating effects with variables which are related to parenting stress. To accomplish these objectives 109 mothers receiving family preservation intervention were interviewed. Their average age was 35.55 years (DT= 7.25), they had at least one children and their level of risk was medium. Psychological symptoms (GHQ-28), parenting experience (PSI-SF, PSOC, PLOC) and coping strategies were assessed (COPE). Analyses showed that most of the mothers exceeded the clinical limit indicated by the GHQ-28 y PSI-SF. Significant relations were observed between psychological symptoms and poverty, stressful life events, parental locus of control and avoidance. Parenting stress was a relevant predictor of psychological symptoms, especially the parental distress scale. Parental satisfaction, problem-focused coping and avoidance moderate this relationship.