Investigating dental caries and fluorosis prevalence over time is an important measure for monitoring trends in oral health. Purpose: This work aimed to describe the prevalence of dental caries and dental fluorosis of 11- to 12-year-old schoolchildren from Iracemapolis, Brazil, in 2004 (n=236) and to compare the current prevalence rates with those from previous surveys carried out in 1991 (n=200), 1995 (n=160), 1997 (n=314) and 2001 (n=244). Materials and Methods: The schoolchildren of both genders from all public schools were examined by two calibrated dentists (Kappa>0.81), using dental probes and buccal mirrors under natural light in an outdoor setting. Dental caries and fluorosis were measured using the DMFT and Thylstrup-Fejerskov (T-F) indexes, respectively. The variation of DMFT index over time was assessed by analysis of regression and the fluorosis prevalence (T-F>1) was compared over time by the Chi-square test at 5% significance level. Results: In 2004, the mean value for DMFT was 1.2; 50% of the children were caries-free, and 15.7% presented dental fluorosis (T-F>1). A significant caries reduction (82.1%) and a significant increase (685%) of fluorosis prevalence have been observed from 1991 to 2004 (p0.01). Conclusion: The results suggest a continuous decrease of dental caries experience and an increase of dental fluorosis prevalence in 11- to 12-year-old schoolchildren from this Brazilian town as well as indicate that further epidemiological surveys should be carried out in order to monitor these trends. Schlagwörter: dental caries, dental fluorosis, schoolchildren