Objectives: The objective of the study was to assess the relationship between fluoride levels and intelligence quotient in children aged between 7 – 11 years in Chittoor district. Andhra Pradesh, India Materials and methods: Ground water from Madanapalli and Tirupathi was collected and fluoride levels were measured using colorimeter test. 960 subjects in the age group 7–11 years were included in the study. Dental fluorosis status was measured using Dean’s fluorosis index 1945. The intellectual ability of each child was calculated using Raven’s colored progressive Matrices (RCPM) and results were analysed. Results: Fluoride levels in drinking water in Madanapalliranged from 2.5 –3.5 ppm and in Tirupathi 1–2 ppm. When both the regions were compared, IQ levels decreased from 21.1198 to 16.5052, which showed a statistically significant difference (p=0.007) Conclusion: From this study it was concluded that there is a significant relationship between fluoride levels in drinking water and intelligent quotient