Objective: To evaluate whether the addition of a wraparound facilitator to regular child protection services improved child and family functioning over 20 months. Method: A single blind randomized controlled trial with concealment and stratification across three sites (N = 135 eligible families with substantiated maltreatment). Results: Based on 2 × 2 mixed analysis of variance and intention to treat, both groups improved in child impairments, d = -0.60 [-0.81, -0.39], caregiver psychological distress, d = -0.33 [-0.52, -0.13], and family resources, d = 0.44 [0.27, 0.62]. No measurable benefit was associated with the intervention (e.g., child impairments, d = 0.14 [-0.12, 0.52]). However, treatment fidelity analysis revealed that many components of wraparound were either missing or present in both groups. Conclusions: The presence of a facilitator alone did not appear to improve child or family functioning if the various components of wraparound were not adequately implemented.