OBJECTIVE: Evaluate the efficacy of 0.8% arginine, potassium nitrate and sodium fluoride mouthwashes on dentine hypersensitivity reduction. METHODS: Six week randomized, double blinded, two cell, parallel single centre clinical study in the Dominican Republic; subjects were randomized into three treatment groups: mouthwash containing 0.8% arginine, PVM/MA copolymer, pyrophosphates, and 0.05% sodium fluoride in an alcohol-free base (arginine); mouthwash containing 2.4% potassium nitrate and 0.022% sodium fluoride (potassium nitrate); a control mouthwash containing 0.05% sodium fluoride (negative control). Tactile and air-blast dentine hypersensitivity assessments were conducted at baseline, thirty minutes post rinsing and two, four, and six weeks of twice-daily product use. For treatment group comparisons, ANCOVA and post hoc Tukey's pair-wise comparisons (α=0.05) were done. RESULTS: Seventy-five subjects were enrolled; 69 subjects completed the study. There were no differences after thirty minutes of a single use, among the three groups with respect to mean tactile and air blast hypersensitivity scores compared to potassium nitrate and negative control mouthwashes (p<0.05). The arginine group presented a statistically significant improvement in the mean tactile scores compared to potassium nitrate and negative control groups after two, four, and six weeks (p<0.001) of product use; the arginine group showed a statistically significant enhancement in air blast hypersensitivity mean scores compared to potassium nitrate and negative control groups after two (p=0.001), four (p<0.001), and six weeks (p<0.001) of product use. CONCLUSION: A mouthwash containing arginine provides a significant and superior reduction in dentine hypersensitivity compared to potassium nitrate and a negative control mouthwash after two weeks.