PURPOSE: This study was conducted to determine the effect of two mouthrinses elmex and Listerine on plaque accumulation in 12-year-olds. MATERIAL AND METHODS: 30 12-year-old children took part in the clinical study. They were divided into three groups. Group I (10 people) was given Listerine to home use. Group II (10 people) was given elmex to home use. Group III (10 people) did not receive any mouthrinses. Following indices were used in first and base study Plaque Index (PI), Approximal Plaque Index (API) and Sulcus Bleeding Index (SBI). The statistical analysis was performed using T test for related samples and Spearman rank order correlations. RESULTS: Mean PI lessened in group I (Listerine) from 0.996 to 0.804 and group II (elmex) from 0.807 to 0.698. In group III it stayed almost at the same level. In all children values of API and SBI decreased after two weeks. Reduce of API in participants using Listerine was important statistically and it lessened from 57.4% to 48.1% (reduction by 16.2%). The other results of API and SBI were not statistically important. API in children using elmex lowered by 15.5%. Bleeding (SBI) in Listerine group decreased by 21.5% and in elmex group decreased by 24.5%. In control group diminish of SBI was only by 14.4%. CONCLUSIONS: In summary, this study has demonstrated that additional rinsing helped in reducing plaque and gingivitis in 12-year-olds but it is not as essential as motivation to everyday oral hygiene.