This study investigated the correlation between sugar consumption and dental caries in a random sample of 184 schoolchildren (all 12 years of age) from public and private schools in Piracicaba, Brazil. A seven-day diet record was administered in a cross-sectional survey. Diet records were used to determine the frequency of sugar consumption both during and between meals. Socioeconomic and behavioral variables were collected in a semi-structured questionnaire. Using Community Periodontal Index (CPI) probes and mirrors and following WHO recommendations, a calibrated dentist assessed the number of decayed, missing, and filled surfaces (DMFS) on permanent teeth, the CPI, and the number of noncavitated (NC) carious lesions. Data analysis demonstrated significant correlations between NC carious lesions and sugar consumption during morning snack (p = 0.0282; r = 0.1618), NC carious lesions and sugar consumption during lunch (p = 0.0539; r = 0.1425), monthly family income and sugar consumption during dinner (p < 0.001; r = 0.2970), father's education and sugar consumption during dinner (p = 0.0027; r = 0.2430), and onset of toothbrushing and sugar consumption during dinner (p = 0.0159; r = 0.1786). A high consumption of sweet foods/beverages occurred between meals (mean = 17.48; standard deviation = 14.68). Although there was no correlation between DMFS and sugar consumption, there was a correlation between NC carious lesions and sugar consumption, indicating that the rational use of sugar is an important factor in caries prevention.