Objective: The aim of this randomized, single-blind, splitmouth design, clinical trial was to evaluate the effectiveness in plaque removal of two brushing methods, the vertical and the horizontal, in a sample of healthy young adults. Method and Materials: Forty-nine subjects were enrolled and 43 completed the study. All subjects abstained from oral hygiene practices for 48 hours. Plaque and gingival abrasions were recorded according to the Rustogi Modified Navy Plaque Index (RMNPI) and the van der Weijden method by one calibrated examiner before and immediately after the brushing session. A dental hygienist performed the two brushing methods using a randomized split-mouth design. The average plaque scores from the whole mouth, interproximal surfaces, and gingival margin were obtained before and after brushing, and the differences were evaluated using one-way analysis of variance. Results: The differences in mean plaque scores between preand postbrushing were statistically significant for both methods. Considering the interbrushing differences, the vertical method produced lower plaque scores compared to the horizontal for the whole mouth (P = .02). In the interproximal surfaces, the vertical method removed more plaque compared to the horizontal one (P .01). In the gingival margin no statistically significant differences in plaque scores were recorded. Only 10 gingival abrasions were registered, mainly produced by the horizontal method. Conclusion: Results suggest that both toothbrushing methods are effective in plaque removal; nevertheless, the vertical brushing method has demonstrated to remove more plaque from the interproximal surfaces than the horizontal method. Palabras clave: dental Plaque Index, horizontal scrub, oral hygiene, toothbrushing, vertical brushing