Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Purpose: The purpose was to evaluate the masticatory performance (MP) of children while also considering body moss index (BMI) and dental conditions. Methods: Ninety-seven 8- to 12-year-olds participated. Dental conditions were appraised by counting the total number of primary and permanent teeth and the decayed, missing, and filled teeth (dmf/DMFT). MP was determined with a chewable material over the course of 20 cycles, obtaining the median particle size (X-50) and broadness of distribution (b). Normal weight, underweight, and overweight/obese groups were formed based on BMI-for-age percentiles. Maternal schooling and socioeconomic status (SES) were assessed. Results: Overweight/obese children presented larger X-50 than normal-weight children. The b and dental conditions were similar among groups. Most families belonged to a very low SES, and most mothers had limited schooling without influence on BMI. X-50 was negatively correlated with age in the underweight group and positively associated with DMFT in the normal group. Underweight children were at higher risk for exhibiting poor MP (odds ratio=1.87). For other variables and groups, the risks were similar. Conclusions: The normal-weight children presented a better masticatory performance than the overweight/obese ones. Poor masticatory performance had a significant relationship with being underweight and with the conditions of permanent teeth in normal-weight children. (Pediatr Dent 2010;32283-8) Received January 24, 2009 vertical bar Last Revision September 26, 2009 vertical bar Revision Accepted September 30, 2009324283288Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)