Decreasing antibiotic effectiveness due to inadequate knowledge and misconceptions on antibiotic usages has been a big threat all over the world including Bangladesh. The aim of the study was to determine the level of knowledge and practice about the rational use of antibiotics among adults in rural area of Rajshahi, Bangladesh. A Community Clinic (CC) based study was performed by involving 600 rural adults. Data were collected from different CC areas in the Rajshahi district, Bangladesh. Knowledge and practice were measured by using composite index. Multistage random sampling and binary logistic regression were used. The study revealed that only 17.2% rural adults had good knowledge about the rational use of antibiotics. The knowledge of proper usages of antibiotics was higher among the young adult compared to older age groups. Adults with primary, secondary and higher educational levels were more likely to have a good knowledge about the rational use of antibiotics compared to illiterate groups. In case of the rural adults, who were secondary and higher educated were more likely to have good practices about the rational use of antibiotics compared with their counterparts. However, majority of the participants (91.0%) had very poor practices in rational use of antibiotic. In this study we found that there was a vast gap of knowledge and practices about the rational use of antibiotics among rural adults in Bangladesh. Consequently, our findings can be considered to make awareness programme about rational use of antibiotic among rural adults in Bangladesh.