The general practitioner has to deal almost daily in his work with the problem of systolic murmurs. He finds such murmurs often in apparently healthy children during a routine check and is then confronted by the question whether to consider these murmurs as of no importance, or to investigate further.There exists a wide discrepancy among publications on the incidence of systolic murmurs in children in general, the percentage varying from 20% to more than 90% (Lessof and Brigden, 1957). Also on the prevalence of what are termed 'innocent' systolic murmurs, Fogel (1957) quotes a range of 8 o to 86-6% from various studies.In order to throw further light on the problem the authors have surveyed the child population of 13 rural settlements and two educational institutions in the Haifa area with regard to the finding of systolic cardiac murmurs. Material and MethodsThe material consists of all cases in which systolic murmurs were found among a total of 2,035 children up to the age of 15 years during the year 1957. Each child with a systolic murmur was investigated with regard to history, physical examination, fluoroscopic, electrocardiographic and related laboratory findings.In all cases blood counts were made in order to exclude anaemia as the cause of a systolic murmur, and sedimentation rates were determined in a search for signs of rheumatic fever or other active processes. To narrow down the margin of subjective error in auscultation, each child was examined by all three investigators. From the results obtained, a survey was made of the incidence and clinical significance of the murmurs heard, considering also sex, age, familial occurrence, occurrence among siblings, and ethnic origin. The children were