AIM: The aim of the present study was to compare the effect of a chewing gum containing 0.50 mg fluoride with two tablets containing 0.25 mg fluoride as NaF, on the salivary and urinary fluoride concentration in children. MATERIALS AND METHODS: Whole saliva and urine were sampled from twenty 5-9 years-old children to assess the baseline fluoride concentrations. The day after, the subjects were asked to chew the fluoridated chewing gum for 15 minutes and saliva samples were collected 5, 10, 30, 60, 120, 240 minutes after ceasing the use of the chewing gum. Urine samples were collected 1, 2, 4 and 24 hours after the use of the gum. After a washout period of one week, the subjects were recalled and were asked to completely dissolve two 0.25 mg fluoride tablets in their mouth. Saliva and urine samples were collected in the same way. Fluoride concentration in saliva and urine was determined using a fluoride specific electrode. RESULTS: No significant differences were found in the concentrations of fluoride in saliva or urine using fluoridated chewing gum and tablets. CONCLUSION: The NaF tablets and chewing gum studied had approximately the same clearance pattern in saliva and urine. These data show that the chewing gum examined could be a valid alternative to the use of NaF tablets in caries prevention.