Comparison of certain features of endemic goitre in the Khumbu district of Nepal and Piedmont is reported. Cases in the younger generations were observed in both areas. In Khumbu, the incidence of goitre in schoolchildren was 75% and cases were even noted in children who had been receiving iodine prophylactic management (injections of iodised oil: 500-1000 mg/yr) for at least three years. The iodine content of drinking water and the most commonly eaten foods was determined. Values were very low and a daily intake of not more than 30 mug was calculated. The findings are in line with metabolic studies carried out by other workers in Upper Khumbu. While it is clear that ambiental iodine deficiency is much higher in Khumbu than in those areas of Piedmont where goitre is most markedly endemic, the inadequacy of preventive iodine administration measures, and environmental features common to both areas, suggest that iodine deficiency is a concomitant factor and not the prime cause of endemic goitre.