Background: Untreated dental caries have considerable consequences on the growth and development of children and their quality of life. Objectives: The aim of this study was to evaluate the prevalence of clinical consequences of untreated dental caries in a sample of Iranian children based on the PUFA/PUFA diagnostic index. Methods: In this descriptive analytical study, 360 students between the ages of 6-12 years were selected using cluster sampling. Oral clinical examinations were performed by one pedodontist. DMFT, dmft, PUFA and PUFA scores were recorded. The height and weight of children were also measured to calculate body mass index (BMI). Descriptive findings are reported in terms of frequencies and percentages, as well as means and standard deviations. The data were analyzed in the Statistical Package for the Social Sciences (SPSS) version 21 using Fisher’ s Exact Test, the Mann Whitney U test, and logistic regression. The level of significance was set at P = 0. 05. Results: The overall caries experience and the overall prevalence of untreated dental caries in the study population was 93. 0% (mean value of 4. 39 2. 78) and 30. 0% (mean value of 0. 57 1. 15), respectively. Components of d/D and p/P had the highest frequencies. Males and females showed no significant differences in terms of prevalence or severity of untreated dental caries (P > 0. 05). The prevalence and mean value of PUFA score were significantly higher in under-weight subjects than in normal children (P < 0. 05). Under-weight subjects had 10 and 3. 5 times greater risk of PUFA and PUFA development, respectively. Conclusions: Our results emphasize the need for further attention to public dental care programs and dental care measures.