To determine the incidence rate, characterize the clinical features and assess the diagnostic evaluation of children presenting with features of acute rheumatic fever (ARF) at two clinics in a region of Fiji where rheumatic heart disease is known to be endemic. We reviewed 5 years (2003-2008) of primary care records from 15 841 patients aged 4-20 years using a pre-determined case definition for ARF; and we reviewed detailed clinical data from 944 cases with features of possible ARF. The crude incidence of first episodes of definite ARF in this setting among patients aged 4-20 years was 24.9 per 100 000 person-years. Joint involvement suggestive of a potential first presentation of ARF but not sufficient for a definite retrospective diagnosis was documented in a further 94 records. There were another 514 cases of joint involvement less suggestive of ARF and 316 cases of unexplained fever with no evidence of localized infection. Patients presenting with potential features of ARF seldom had a diagnostic evaluation sufficient to exclude its diagnosis. The incidence of ARF at these clinics is nearly twice that reported in a local hospital-based study, but it is likely to under-represent the actual number of cases presenting to primary care. There is a need for better surveillance for ARF and to develop simple and practical approaches to diagnosing ARF in primary care in low-resource settings.