Objectives: Camurati-Engelmann disease (CED) is a rare autosomal dominant genetic disorder caused by mutation of TGFB1 on chromosome 19q13.1. TGFβ plays a role to inhibit adipogenesis and bone resorption and enhance bone formation and CED manifested with progressive bone thickness, muscle weakness, and low subcutaneous fat. Losartan as an anti-TGFβ effect have been introduced for CED patients to reduce bone pain and increase physical activity. In this study, we demonstrated the effectiveness of losartan in bone turnover and body mass index in CED patients. Methods: We used losartan as a treatment for three related Korean CED patients including two siblings, a 10-year-old boy, a 6-year-old girl, and a 45-year-old mother. The heterozygote of p.R218C in i＞TGFB1/i＞ was identified in this family. After genetic confirmation, all subjects treated with losartan and the dose was gradually increased from 1 mg/kg/d to 1.5 mg/kg/d and 2 mg/kg/d every 3 months. Every 3 months, the body weight, height, body mass index (BMI) and pain score were measured and serum bone specific alkaline phosphate (BAP), C-terminal telopeptide (CTX) or N-terminal telopeptide were performed before medication and CTX and BAP were follow-up every 6 months. Results: All of the subjects had low BMI (mean -2.73 SDS) and diaphyseal thickening of long bone on X-ray. One year after losartan administration, not only reduced pain score but also weight gain was observed and the mean BMI was increased to -2.48 SDS. The Tanner stage was I in two siblings and mother was in menopausal state 2 years ago. The BAP level representing bone formation was decreasing (mean difference -12.9 μg/L) at last evaluation. In CTX level, older brother showed increasing CTX level (from 0.60 to 1.17 μg/L) but it was decreasing in a younger sister (from 1.52 to 1.01 μg/L) and a mother (from 0.91 to 0.48 μg/L) after losartan. Two children were tolerated with 2 mg/kg/d of losartan, but the mother complained of dizziness at dose of 100mg/d of losartan and reduced to 25mg/d at 12 months. Conclusions: Three related CED patients showed improving BMI and decreasing BAP after one year of losartan. Beside steroid treatment, TGFβ antagonist may be an alternative and effective drug to modify the disease course including poor weight gain and progressive bone formation in CED patients.