This study has dealt with the primary cause for tooth extraction on 2760 permanent teeth, extracting third molars , in patients with an age ranging from 10 to 90 years excluding and an average age of 40.2 years. The first cause in caries(67.7%) periodontal reasons come second (25.9%), and all the other causes account for 6.4%. A special pattern of relationship between caries and periodontal diseases as factors causing tooth extraction has become evident, with the latter being the main reason for tooth extraction in middle age (45-54years) ata rate of 49.8% versus 46% for carries-related extractions. Caries, however, is the chief cause for tooth extraction at ages under 45 and over 54 years (81.9% , 53.1%); this is also true of the age group 10-19 years (75%), while extractions for orthodontic reasons account for 21.7%. No significant differences have been observed between males and females,or between the right and left side of the jaws. Yet, extractions of all tooth types in the upper jaw have been more frequent than those in the lower jaw, with the exception of first molars.