Statement of problem: Basically as a matter of fact, it is important to determine the status of third molars before many of the children's dental treatment. The pattern of development and growth of face, jaw and teeth differs from race to race. Therefore, studies on the third molar status in each population seem to be an important issue.Purpose: This study was performed to determine the pattern of the third molar development in a group of Iranian children and adolescents, in order to province a suitable reference for clinical use and future studies.Materials and method: In this descriptive study, 757 panoramic radiographs of patients, 6-16 years old, were investigated and the development of the third molars was categorized based on nine stages. The data were analyzed with chi-square and paired samples tests.Results: The most important results of this study were:1. The earliest and latest ages with the possibility of observing the signs of wisdom tooth crypt in panoramic radiographs, were six and 14 years respectively.2. Among the investigated ages, the highest possibility of observing finding the first sign of third molar crypt emergence was found to be at the age of nine.3. Possibility of the third molar existence after age of 10 reduces about 53% in comparison to the earlier ages.4. There was a significant difference between age and the third molar developmental stage in each four quadrant (p=0.000).Conclusion: Determination of the pattern of third molars development stages is useful in clinical diagnosis and comprehensive treatment plan.Key words: Dental development, Third molar, Panoramic Radiography