Background: Acute pharyngitis is one of the most common illnesses. Most acute cases are caused by viral infections. To enhance the appropriate prescribing of antibiotics a number of clinical prediction rules have been developed to distinguish streptococcal pharyngitis from pharyngitis by other causes Aim: To assess the appropriateness of antibiotic prescribed to cases of acute pharyngitis and the diagnostic accuracy of the McIsaac modified Centor score for predicting group A beta hemolytic streptococcal pharyngitis. Patients and Methods: A cross-sectional study; was conducted in Port Said fever hospital, Ismailia fever hospital and Suez fever hospital, within the area of Suez Canal, including. The study included 196 patients who presented to these hospitals between the age of 3 and 65 years. Results: Antibiotics were prescribed to 86% of patients while the prevalence of group A beta hemolytic streptococcus (GABHS) pharyngitis was 12.8%. A broad spectrum third-line agents or a non recommended antibiotics were prescribed to 62% of patients. McIsaac score was found to be 100% sensitive and 63.16% specific giving 28.41% a positive predictive value and a negative predictive value of 100%. Conclusion: Antibiotics are prescribed inappropriatly to patients with acute pharyngitis and McIsaac score is a useful clinical to for diagnosis of GABHS pharyngitis and its use decreases antibiotic prescription.