• To determine whether suboptimal nutrition affected growth deceleration in patients with constitutional delay of growth (CDG), retrospective weight and growth data and a cross-sectional nutritional assessment was performed. Patients studied included 52 CDG children with delayed bone age and 15 children with familial short stature without bone age delay. Body weight and length-height progression were evaluated from birth to 12 years using z scores. Clinical anthropometry, biochemical, and dietary evaluation were performed at the initial evaluation. Significant differences were noted between patients with CDG and familial short stature in their W/L ratio and W/H ratio profiles from 4 months to 12 years. Mean creatinine-height index, retinol binding protein, serum iron, and transferrin saturation values were lower among young CDG patients. These data suggest that suboptimal nutrition early in infancy may contribute to the course of CDG.