The aim of the present study was to evaluate the effect of two chlorhexidine rinsing solutions (0.12% and 0.2%) on plaque and gingival bleeding. Ten dental students participated in this double-blind, cross-over study, rinsing twice a day, for one minute, with each one of the tested solutions for fourteen days. A wash-out period of one week between treatments was observed. In order to assess gingival bleeding, the van der Weijden et al. 1 (1994) index was used. The plaque indexes used were those of Quigley, Hein 2 (1962) and Silness, Löe 3 (1964). In the pre-experimental period, subjects received oral hygiene instructions and dental prophylaxis. The results revealed no significant differences between both concentrations in relation to plaque and gingival bleeding. Mean values (± standard deviation) of the Quigley & Hein index were 0.25 ± 0.16 for the 0.12% solution and 0.23 ± 0.26 for the 0.2% solution (p = 0.4838). Mean values (± standard deviation) of the Silness-Löe index were 0.12 ± 0.10 for the 0.12% solution and 0.11 ± 0.11 for the 0.2% solution (p = 0.7592). The bleeding index mean values at the end of the study were not different for both concentrations with mean values (± standard deviation) of 14.93% ± 6.68% and 13.95 ± 9.24% for the 0.12% and 0.2% solutions, respectively. Although an increase in gingival bleeding was observed, both concentrations were able to control dental plaque.