Clinical guidelines provide continuing education and help physicians in the clinical decision-making process. Clinical guidelines to manage acute respiratory infections (ARI) were developed comprehensively from a perspective where prevention, diagnosis, treatment and the patient's education were considered. Methodology. The guideline development process was comprised of two stages: 1. The building stage consisted of several steps: definition of the problem, definition of the potential users of the guidelines, and the appropriate level of care; review of updated bibliographies, and validation using the Delphi technique. 2. The start-up stage consisted of evaluating the guidelines applicable to out-patient settings. Twenty family physicians participated, using the guidelines with 115 patients. Agreement between the family physicians' diagnosis and the criteria stated in the guidelines was tested using unweighted kappa. Differences in the use of the guidelines to manage ARI patients were tested by using the X2 test or the exact Fisher test. Results. Development of guidelines considered the patient's age group. Therefore, guidelines to manage patients under five years of age and to manage patients above this age were constructed. The application of the guidelines was increased from 40 to 60%. As a result, inappropriate prescribing of antibiotics and cough syrups decreased. Although the guidelines could be helpful in treating ARI, its efficacy and effectiveness remain to be tested.