Background: Numerous epidemiological studies were conducted in Iraq, concerning dental caries and related etiological factors however; most of these studies were concerned with pre-and primary school children and/or those at index ages (12-15years old). At the time studies regarding older ages are very limited. This study was done to determine the prevalence and severity of dental caries and treatment need among high schools girls (16-18 years old) in Al-Mussayb city, Babylon Governorate. Thus, it can be considered as a base line data that allows studying dental caries among permanent dentition, also allows the comparison with other studies in other parts of the world. Material and Method: A total number of 900 high school girls were examined in their classroom following the method of WHO. Recording of dental caries was by application of DMFT/DMFS index, and dental treatment needs following criteria of WHO. Results: The prevalence of dental caries was 70.5% with a mean DMFT/DMFS values (3.30 ±SE 0.091, 4.94 ±SE 0.161) respectively. A statistically highly significant increase of caries-experience was recorded with aging. The highest percentage of girls needed one surface restoration (60.8%). Conclusion: A relatively high caries – experience was present among high school girl in Al Mussayb city indicating the need for preventive programs.