Background: Some skiers suffer from medical symptoms during or after skiing, especially downhill skiing. However, there has been no investigation on medical problems in skiers. In this study, our main objective was to evaluate the FREQUENCY of medical symptoms during or after ski among Iranian skiers.Methods: This cross sectional descriptive study was performed in winter of the year 2005, at Dizin piste (Iran). We evaluated demographic data and medical history of skiers, as well as the FREQUENCY of medical symptoms during ski using a questionnaire. The relations between sex, medical and drug history, smoking habits, and symptoms were assessed by chi-squared and fisher’s exact test. The relation between age, duration of skiing, history of previous skiing (in years) and symptoms was analyzed by means of independent t- test. P <0.05 was considered significant.Findings: Out of 1448 skiers, 74% were male and the mean age of subjects was 25.2 (±8.4) years. A total of 1208 skiers wore medical glasses or lenses during skiing, and visual disorders were found in 15.2% of skiers. Among all subjects, one medical symptom was found in 20.1% and two medical symptoms or more in 3.6%. The most common clinical profile was headache, nystagmus and true vertigo. Occurrence of symptoms had significant association with wearing glasses or lenses during routine life, habit of smoking and previous ski injury. Alcohol consumption was seen in 31.2% skiers, and it had a borderline relation with incidence of symptoms. There was not any association between incidence of symptoms and sex, age, duration of skiing, wearing glasses or lenses during skiing, and history of motion sickness. Conclusion: There were at least two symptoms in 3.6% of skiers. This finding shows ski sickness is different from other altitude sicknesses.