A cross-sectional study was conducted over a 1-year period (1 January-31 December 2000) during which cases suffering from uncomplicated tonsillopharyngitis were recruited from the private and public health services in Alexandria. The objective was to determine the prevalence of group A-beta haemolytic streptococci (GABHS) among children suffering from tonsillopharyngitis and to identify the clinical criteria predicting GABHS pharyngitis in children. A total of 578 children aged between 1 and 15 years with a mean of 6.3 +/- 3.7 years, presenting with sore throat were enrolled in the study. Demographic data and presenting signs and symptoms for each patient were recorded on a standardized form and a throat swab was taken using the filter paper technique. The overall prevalence of GABHS was 17 per cent and the highest isolation rate was reported in children aged 10-15 years. Non-GABHS comprised 11.9 per cent of the total isolates. The most prevalent of them were group C and G streptococci. The highest frequency of both GABHS and non-GABHS was in early spring. Significant predictors of GABHS pharyngitis were: age 10-15 years, the presence of dysphagia, vomiting, pharyngeal exudate, and scarlatiniform rash. Watery eyes and/or rhinitis had a protective value against the diagnosis of GABHS pharyngitis, while fever was considered to be a non-specific finding in cases with GABHS pharyngitis. Antibiotic sensitivity test showed higher sensitivity to both penicillin and erythromycin. Only 1 per cent of the GABHS isolates showed resistance to cephadroxil. We concluded that a syndrome of signs and symptoms could be used as a clinical predictor for the diagnosis of GABHS pharyngitis.