The prevalence of recurrent caries was recorded at the annual examinations of a 3-year double-blind caries clinical trial involving 4,294 children age 12-13 years at baseline. Recurrent caries was defined as clinically apparent disease affecting the restoration margins. Examination of all surfaces of undried teeth was carried out using a CPITN-C probe. The proportion of children with recurrent caries was 7.5, 9.5, 6.3 and 8.0% at baseline, year 1, year 2, and year 3. The proportions of restorations with recurrent caries was 1.9, 1.8, 1.0 and 1.1%, respectively, at each examination. A number of oral hygiene parameters were collected via a computer questionnaire. Water rinsing after brushing proved to be associated with recurrent caries (p < 0.01), those using a beaker having more recurrent caries than those using less diluting methods. Subjects who brushed twice a day (at the final examination) had less recurrent caries than those reporting to brush less often (p < 0.01). Both these results are consistent with previous findings on the association between DMFS increments and oral hygiene practices.