Seventeen children with active rheumatic fever(ARF), age ranged from 4 to 13 years, 17 children with inactive rheumatic heart disease (IRHD), age ranged from 6 to 16 years and 17 age and sex matched healthy children were tested for the following:: 1. Complete clinical examination 2. Laboratory investigations ( complete blood count, ESR, CRP, and ASOT. 3. Monocyte yeast cell phagocytosis and serum opsonic activity . Results showed that the mononuclear phagocytic function was significantly lower in rheumatic children than in control. After opsonization with normal serum , the monocyte phagocytic function was significantly lower in ARF group than in the IRHD group. The serum opsonic activity in our rheumatic subjects was normal. We speculate that an inherent phagocytic abnormality in such patients may result in failure of clearance of immune complexes that have been condemned in the pathogenesis of rheumatic fever.