Background & Objectives: Respiratory distress is one of the most important causes of children admission in hospitals. In most cases, it is due to pneumonia, asthma or acute bronchiolitis. Since theses diseases have a lot of symptoms in common, we decided to study these disorders in more details to facilitate the appropriate diagnosis and treatment based on clinical, laboratory and radiologic findings.

  Methods: 238 children who suffered from respiratory distress and were admitted to pediatric ward in Ghaem hospital were studied. This descriptive study was performed during 3 years including 2 retrospective and one prospective year. The relationship between variables was analyzed using chi-square test.

  Results: The patients were six months to five years old. Pneumonia (40.3%) asthma (30.3%) and bronchiolotis (16.8%) were the most common causes of respiratory distress. Totally, 61.1% of the patients were male. The mean age of the patients was 10.3 months in bronchiolitis and 36.6 months for asthma. The most common symptom among these three diseases was tachypnea. Most of the patients were admitted in winter and fall respectively. The main radiologic pattern in pneumonia was pulmonary infiltration and for asthma and acute bronchiolitis it was pulmonary hyperinflation.

  Conclusion: Proper attention to signs and symptoms as well as laboratory and radiologic fndings is necessary for accurate diagnosis. In this study the most common cause of respiratory distress in children under 5 was found to be pneumonia, asthma and bronchiolitis respectively.