Personal exposure levels to respirable suspended particulates during cooking periods were monitored in twenty households in a rural community of the hill region of Nepal. Filters for gravimetric analysis were exposed in households with traditional stoves (without flue) and then again after the introduction of smokeless (with flue) cook stoves. Drager Tube analyses of carbon monoxide and formaldehyde levels were also conducted. Data from this longitudinal study provide convincing evidence of the cause-effect relationship between the introduction and use of smokeless stoves and the resulting decrease in domestic smoke pollution. A household survey revealed that all cooks, but one, found that the smokeless stove emitted less smoke than the traditional stove and seventy-five percent of the cooks preferred the smokeless stove to the traditional stove.