Objectives:Calprotectin is a calcium- and zinc-binding protein and a marker in faeces of gastrointestinal inflammation. Reference values have been established in children older than 4 years. The aim of the present study was to determine the concentration of faecal calprotectin (FC) in human immunodeficiency virus (HIV)âinfected, highly active antiretroviral therapyânaïve Ugandan children and compare it with the reference value.Methods:We tested 193 HIV-infected children ages 0 to 12 years in a hospital-based survey for FC. A standardised interview with sociodemographic information and medical history was used to assess risk factors. A cluster of differentiation 4 (CD4) cell percentage was prevalent in all of the children.Results:The median FC concentrations decreased with increasing age, as in healthy children. The median concentration was 208 mg/kg in infants 0 to 1 year, 171 mg/kg among toddlers 1 to 4 years, and 62 mg/kg for children 4 to 12 years. Children with advanced disease and a low CD4 cell percentage had significantly higher FC concentrations than those with a high CD4 cell percentage. Children older than 4 years with diarrhoea had significantly higher FC concentrations compared with those without diarrhoea.Conclusions:HIV-infected children older than 4 years had a median FC concentration above the reference value, and gut inflammation in the children with elevated values is likely. Children with more advanced disease had increased FC concentrations regardless of age.