OBJECTIVES: Acute tonsillopharyngitis (AT) is caused by Group A beta-hemolytic streptococci (GAS) in fewer than 30% of children. There is a risk-benefit tradeoff when considering whether to test and/or treat. On the one hand cost of testing (throat culture and express-technique) is comparatively higher than cost of antibacterial treatment; on the other hand overtreatment promotes drug resistance and may produce unnecessary adverse reactions. METHODS: Three strategies were considered: 1) Treat all patients with penicillin V, 10 days (RxALL); 2) Use express-test to detect GAS and treat patients with positive results (ET+/Rx); 3) Culture to detect GAS and treat patients with positive results (C+/Rx). Baseline estimated values for variables included the probability of positive culture in children with clinical symptoms indicating the GAS etiology (0.4 – our own data), sensitivity of express-test (0.65) – Directigen, Becton Dickinson, USA (available in Russia) and sensitivity of culture (0.9). Finally for each strategy a cost/effectiveness ratio (C/E) was calculated, where C was costs of tests, cultures and Rx from the perspective of a second–party payer; E was Correct Treatment Decision (culture positive patients who were treated and culture negative patients who were not treated). Decision analysis was done with DPL software (ADA Inc). Sensitivity analyses were applied to analyze the impact of varying the probability estimates and cost variables. RESULTS: C+/Rx was the most cost-effective strategy (C/E=229), followed by RxALL (C/E=248) and ET+/Rx (C/E=786). Sensitivity analysis comparing C+/Rx to RxALL showed that C+/Rx was sensitive to changes in several variables. Specifically, RxALL was preferred if: The cost of Rx decreased (<0.9); cost of culture increased (>2.02); sensitivity of culture decreased (<0.59). CONCLUSIONS: C+/Rx is the preferred strategy in the decision-making process for antibiotic treatment of acute tonsillopharyngitis in Russian children.