ObjectiveTo evaluate the impact of fetal alcohol spectrum disorder (FASD) on child and family functioning.DesignProspective survey.SettingMultidisciplinary FASD assessment service.PatientsCaregivers of 35 children with FASD.Main outcome measuresChild-health-related functioning (Royal Alexandra Hospital for Children Measure of Function (MOF)), family impact (Impact on Family (IOF) Scale), impact on siblings and caregiver stress.ResultsMost caregivers were foster carers (74%). Children with FASD (median age 8.7 years; 54% male) were a median of 7.0 years at diagnosis. Regarding child-health-related functioning, 43% reported moderate, severe or major problems in at least one area on the MOF. IOF was moderate (60%) or high (34%). Poorer child-health-related functioning was associated with greater impact on family. Unaffected siblings received less parental attention and displayed anger or frustration about the affected child’s needs. Caregivers reported frequent and high levels of stress.ConclusionsFASD impacts children’s health, and function of the family and unaffected siblings. These novel findings highlight the need for family-oriented service development.