Background: Tobacco smoking may cause skin aging through mast cell proteinases. Objective: To compare the numbers of mast cells showing tryptase and chymase in the healthy-looking skin of smokers and non-smokers. Methods: The study subjects consisted of 80 males, 42 of whom were smokers and 38 non-smokers. A skin biopsy from the medial arm was processed for immunohistochemical staining of tryptase and chymase, as well as chymase inhibitors alpha-1-proteinase inhibitor (alpha-1-PI) and alpha-1-antichymotrypsin (alpha-1-AC). Results: The number of tryptase+ mast cells was significantly higher in the smoker group (84 ± 32 cells/mm2) than in the non-smoker group (70 ± 32 cells/mm2) (p = 0.044). Likewise, the number of chymase+ mast cells was higher in the smoker group (89 ± 20 vs. 80 ± 22 cells/mm2), though statistical significance was not reached (p = 0.07). No significant difference was observed in alpha-1-PI+ and alpha-1-AC+ cells. Conclusion: Especially tryptase, but probably also chymase, may have an influence on the skin of smokers, such as wrinkling and aging.