Arsenic poisoning of tubewell water, which constitutes the primary source of drinking water, has become the greatest health threat to the people of rural Bangladesh. Somewhere between 35 to 57 million people in the country are now suspected of being affected by drinking water contaminated with arsenic. While the Bangladesh government, non-government organizations (NGOs), and bilateral and multilateral assistance agencies are involved in combating this dreadful problem, all of their efforts to date have proceeded without having grassroots information about arsenic poisoning. The objectives of this study are to investigate the level of knowledge rural residents have regarding arsenic poisoning and to identify the correlates of that knowledge. Questionnaire surveys administered among residents of four rural areas in Bangladesh provided the major data source for this study. Twenty villages were selected from moderate and low arsenic risk regions and a total of 356 respondents, 177 from medium risk regions and 179 from low risk regions, were interviewed. Analysis of the survey data reveals that arsenic awareness is currently not widespread in the study villages, particularly in the low arsenic risk region. There are also gaps in arsenic knowledge regarding the diseases caused by arsenic poisoning and mitigating measures available to prevent contamination. This study identified arsenic risk region, level of education, gender, and age as important determinants of arsenic knowledge. The findings of this study will aid in making existing health education programs more effective and in reducing the risk of developing arsenic-related illnesses.