Objective: In Egypt, acute rheumatic fever (ARF) is the most common cause of acquired heart disease. ARF is a clinical syndrome without a specific diagnostic test or single pathognomonic feature, so the aim of this study is to investigate the utility of using serum total sialic acid (TSA) in differentiation between children suffering from ARF with and without carditis. Methods: In the present study, 62 children were divided into three groups: first group, 16 healthy children; second group, 20 patients suffering from chronic rheumatic heart disease (RHD); and third group, 26 patients suffering from ARF, subdivided into three subgroups as (A) 10 patients suffering from arthritis without carditis, (B) 10 patients with carditis but without congestive heart failure (CHF), and (C) 6 patients with carditis and CHF. Antistreptolysin O titre (ASOT) by latex agglutination test, erythrocyte sedimentation rate (ESR) by Westergren method, C-reactive protein (CRP) by turbidimetric immunoassay method, lactate dehydrogenase (LDH) activity by kinetic method, immunoglobulin levels by radial immunodifussion assay (RID), cardiac troponin I (cTnI) by ELISA test kit and TSA by diphenylamine (DPA) method were performed. Results: Significant elevated values of ESR, CRP, LDH, IgG and IgA were obtained in ARF as compared to both control and RHD groups; significant values of IgM were found between B and C as compared to control and RHD groups; cTnI showed insignificant difference between all groups; values of TSA showed highly significant difference between ARF as compared to both control and RHD groups as well as between RHD and control groups; significant difference was found between B and C groups as compared to group A. Conclusion: The results of the present study point out the possibility that the levels of TSA could be of help in differentiation between ARF patients with and without carditis. [J Exp Integr Med 2012; 2(4): 305-311