This article develops a clinical indicator of household energy security and assesses possible associations with food security, health, and developmental risk in children ≤ 36 months of age. As household energy insecurity increases, infants and toddlers experienced increased odds of household and child food insecurity and of reported poor health, hospitalizations, and developmental risks.  Pediatric health care providers need to be aware of the energy security status of their patients’ households and use this information to inform decisions regarding both treatment and referrals for other services.