Background: The aim of this study is to investigate the prevalence of subclinical rheumatic heart disease in schoolchildren aged 5-18 by using portable echocardiography in Ankara, Turkey.Methods: The portable echocardiography screening was performed by a paediatric cardiologist for all of the cases. The mean age of 2550 healthy students was 11.09 ± 2.91 years (1339 females, 1211 males) in three private and three public schools. Echocardiographic studies were assessed according to 2012 World Heart Federation criteria for rheumatic heart disease.Results: After reviewing the echocardiographic images, 73 students were reevaluated by an advanced echocardiography device in the university hospital. Evidence of definite subclinical rheumatic heart disease was found in 39 students (15/1000) and borderline rheumatic heart disease in 20 students (8/1000). No children had any clinical symptoms. The mean age of children diagnosed with rheumatic heart disease and borderline rheumatic heart disease is 12.4 and 11.4 years, respectively. The risk of rheumatic heart disease was found to be increased sevenfold in girls between 14 and 18 years. We surprisingly observed that the prevalence of definite rheumatic heart disease in private schools located in high-income areas of Ankara was higher than that in public schools.Conclusions: This is the first and largest single-centred echocardiographic screening study for subclinical rheumatic heart disease in Turkish schoolchildren. The frequency of rheumatic heart disease has been found to be 15/1000. This finding is similar to those of recent echocardiographic screening studies performed in middle and high-risk populations. We conclude that to decrease the burden of rheumatic heart disease, echocardiographic screening studies are necessary, and long-term follow-up of children with echocardiographically diagnosed subclinical rheumatic heart disease is needed.