Objective.—To determine the incidence of and risk factors for acute mountain sickness (AMS) in native Nepalese children during a pilgrimage trip to Gosaikunda Lake in the Langtang National Park Region of Nepal (elevation 4380 m).

Methods.—A descriptive, noninterventional, cross-sectional study was completed on a group of children during the pilgrimage to Gosaikunda. Participants were interviewed about the symptoms of AMS using the Lake Louise Scoring System.

Results.—Thirty-six children between 3 and 15 years of age were interviewed after a rapid ascent (over 1 to 3 days) from 1950 m to 4380 m. Acute mountain sickness was diagnosed in 17 of 36 (47.2%) children. The sickness was seen in only 5 of 20 (25%) children who took 2 or more days to ascend, compared with 12 of 16 (75%) children who spent only 1 night (reaching the study site at Gosaikunda on the second day) to complete the same ascent (P ≤ .01, odds ratio [OR]  =  9.0, 1.61 < OR < 57.36). No significant correlation was found between the incidence of AMS and gender, previous exposure to high altitude, or concurrent illness.

Conclusions.—Our results indicate that the incidence of AMS in this group of Nepalese children was high and associated with rapidity of ascent. Rapid ascent to high sleeping altitude and increased physical activity were observed as possible risk factors. We suggest organizing educational programs to make children and their parents aware of altitude-related problems and advise gradual ascent to such high-altitude pilgrimage sites.