Indicators for cooking fuel pollution are needed to determine the extent of fuel-related problems in developing countries and to assess the success of measures undertaken to reduce such problems. It is proposed that eye irritation in the form of tears or smarting eyes during cooking time [tears while cooking (TWC)] is a useful determinant of indoor air pollution from cooking-related sources. An analysis of data from three cities (Lusaka, Maputo, and Hanoi) showed that TWC is more prevalent in conditions of higher particulate pollution. Persons experiencing TWC were also found to have more respiratory symptoms. The prevalence of TWC provides a good indicator of groups that are at greater risk of health impairment due to indoor air pollution. Surveying for this condition is simple and nonintrusive, which makes it a useful screening indicator, though it cannot replace more thorough investigations in epidemiological studies. It can, however, be used in guiding interventions to the most needy groups. It can also be used to assess the success of measures introduced to reduce pollution hazards relating to the cooking environment, such as improved stoves, chimneys, and kitchen improvement.