Mountain guides encounter extreme UV doses due to the outdoor workplace, altitude-related increase of UV radiation, and UV reflection from snow-covered surfaces. Mountain guides have more sunburns and are more often affected by UV-related skin damage. Occupational UV exposure was an independent risk factor for solar cheilitis and basal cell carcinoma. The high prevalence of seborrhoeic dermatitis, herpes labialis, and common warts may be due to UV-linked immunosuppression. Skin cancer in mountain guides is likely to be an occupational disease.