This study is a record of ethnomedicinal knowledge in Begumganj province focussed on medicinal plants and their local uses for primary health care. The aim was to document and preserve the ethnomedicinal knowledge used by traditional healers of Begumganj upazila, Bangladesh, to treat human diseases and evaluate the relative efficacy of the medicinal plants. The uses of medicinal plants were documented as an ethnomedicinal data sheet using direct observation, field interview, plant interview and group interview techniques from December 2012 to January 2014 in the study area. Data were collected from 98 traditional healers through a questionnaire survey and analyzed through informant consensus factor and fidelity level. This study revealed comprehensive relationship among various diseases and families, forms and parts of plants and modes of preparation. Overall, 75 plant species under 71 genera of 47 families were documented, which are used to treat 41 diseases. Data analysis revealed that 41.33%, 14.67%, 36% and 8% of the medicinal plant species were herbs, shrubs, trees, and climbers, respectively. Leaves were the most used parts, followed by stem, root, fruit, bark, latex and rhizome. The most frequently treated diseases were dysentery, rheumatism and skin diseases. This is the first ethnobotanical survey, which recorded the importance of medicinal plants in Begumganj upazila, Bangladesh.This study can contribute to preserving the indigenous knowledge on the traditional use of medicinal plants in this region and new drug development with attracting future generations towards traditional healing practice.