BACKGROUND: The morbidity and nuisance factor associated with bites from mosquitoes and other insects are one of the many hazards faced by travelers, including those to the Arctic. A predeparture literature review suggested that insect bites were such a large problem in the area to be visited that they would probably have a significant impact on expedition activities. Therefore, we set out to assess the extent of the insect biting nuisance, focussing particularly on interference with expedition activities, in order to make recommendations for future expeditions to this area. The number of bites and their effects was examined on a 6-week British youth expedition to Alaska in July/August 1999. METHODS : A weekly "Insect Biting Nuisance Questionnaire" was distributed to each expedition member (total 72) to record the number of bites received over the previous week, a subjective grading of severity and itchiness, the extent of interference with expedition activities, any complications from the bites, and details about prevention and treatment. RESULTS: The questionnaire response rate was 64%, which was a representative sample. The median number of bites per person over the entire 6-week period was 33, with females and younger expeditioners tending to receive more bites. Multivariate analysis suggested that younger age was associated with more severe and itchier bites. Sleep was disturbed by itching on only 4% (68/1918) of nights. Generally, the bites were thought not to interfere with expedition activities (median score for interference 0; range 0-10). CONCLUSION: The number of bites and their impact on expedition activities were both lower than expected. Thus, it is recommended that expeditions and independent travelers to this area do not need to increase time spent in the field to compensate for expedition man days lost due to problems associated with the insect biting nuisance.