Objective: This study aimed to compare the efficacy of low-level laser (LLL) and desensitizing paste (DP) containing 8% arginine-calcium carbonate, in the treatment of dentin hypersensitivity (DH) and also to determine whether their combined application would improve the efficacy of the treatment. Background data: There are various options for the treatment of DH; however, superiority of one method over others alone has not been currently demonstrated. Materials and methods: Twenty-one patients with 156 teeth affected by DH were included in the study. Selected teeth were randomly divided into five groups: LLL, DP, laser followed by DP (LLL+DP), DP followed by laser (DP+LLL) applied to one of the quadrants, and a control group, consisting of a randomly selected additional tooth in one of the quadrants. Teeth were irradiated by the 685 nm diode laser treatment with 25 mW at 9 Hz for 100sec at 1 cm(2) area (2J/cm(2)) in interrupted mode. Pain response to evaporative stimulus was quantified on a visual analogue scale (VAS) over a 90-day period. Results: All four treatment groups experienced significant and persistent decrease in the mean VAS score immediately post-treatment until the end of the study, whereas the placebo group had high VAS scores throughout the study. On day 90, percent reduction in VAS scores was 72% for LLL, 65.4% for DP, 54.6% for LLL+DP, and 69.6% for DP+LLL, whereas the placebo group showed an increase of 7.8%. Conclusions: The application of either LLL or DP containing 8% arginine-calcium carbonate appears to be effective in decreasing DH. However, their combined use does not improve the efficacy beyond what is attainable with either treatment alone.