Background Few successful treatment modalities exist to address childhood obesity. Given Latinos’ strong identity with family, a family-focused intervention may be able to control Latino childhood obesity. Purpose To assess the feasibility and effectiveness of a family-centered, primary care–based approach to control childhood obesity through lifestyle choices. Design Randomized waitlist controlled trial in which control participants received the intervention 6 months after the intervention group. Setting/participants Forty-one Latino children with BMI >85%, aged 9–12 years, and their caregivers were recruited from an urban community health center located in a predominantly low-income community. Intervention Children and their caregivers received 6 weeks of interactive group classes followed by 6 months of culturally sensitive monthly in-person or phone coaching to empower families to incorporate learned lifestyles and to address both family and social barriers to making changes. Main outcomes measures Caregiver report on child and child self-reported health-related quality of life (HRQoL); metabolic markers of obesity; BMI; and accelerometer-based physical activity were measured July 2010–November 2011 and compared with post-intervention assessments conducted at 6 months and as a function of condition assignment. Data were analyzed in 2012. Results Average attendance rate to each group class was 79%. Socio-environmental and family factors, along with knowledge, were cited as barriers to changing lifestyles to control obesity. Caregiver-proxy and child-self-reported HRQoL improved for both groups with a larger but not nonsignificant difference among intervention vs control group children (p=0.33). No differences were found between intervention and control children for metabolic markers of obesity, BMI, or physical activity. Conclusions Latino families are willing to participate in group classes and health coaching to control childhood obesity. It may be necessary for primary care to partner with community initiatives to address childhood obesity in a more intense manner. Trial registration This study is registered at Clinicaltrials.partners.org 2009P001721.