Children with neurofibromatosis type 1 (NF1) tend to be macrocephalic and short. Our aim was to define the incidence and diagnostic accuracy of elevated head circumference-to-height ratio (HCHR) in children with NF1 and to assess if elevated HCHR would facilitate early diagnosis of NF1. Retrospective analysis of growth and health data of 80 NF1 patients aged 0-7 years was performed. The incidence and diagnostic accuracy of elevated HCHR for NF1 was analyzed using receiver operating characteristic curves. The median age when the first elevated (≥2.0 SDS) HCHR value was detected was 0.3 years (range 0.0-5.3). At the median age of diagnosis (3.6 years), 53.8% of NF1 children exhibited elevated HCHR. The diagnostic accuracy of HCHR alone was 0.78 (95% CI 0.72-0.84), but in comparison with the seven National Institutes of Health diagnostic criteria for NF1, elevated HCHR was the second most prevalent feature. Elevated HCHR is an early and frequent feature in NF1 children. Taking HCHR into account would facilitate the early detection of NF1.