Religiosity is considered as one of the many factors shaping an individual’s health consciousness. The aim of the study is an analysis of the correlation between the religiosity of Jehovah’s Witnesses and their attitudes towards health and disease. A cross-sectional study was performed on the convenience sample of 171 Jehovah’s Witnesses from eastern Poland with the use of two research tools: the author’s questionnaire, focusing on attitudes towards health, disease, death and the use of stimulants, and the Duke University Religion Index (DUREL). The research involved 99 females (57.9%) and 72 males (42.1%), with an average age of 37.25 (SD = 12.59) years. On average, they have been a Jehovah’s Witness for 29.21 (SD = 13.22) years and are characterised by a high ratio of organisational religious activity (ORA) (M = 5.60; SD = 0.62) and intrinsic religiosity (IR) (M = 4.81; SD = 0.37). Those who had never smoked before becoming one of Jehovah’s Witnesses had a higher IR (Z = −2.822; p = 0.005), similarly to those respondents who smoked cigarettes before they became Jehovah’s Witnesses (Z = −2.977; p = 0.003) and those who did not abuse alcohol before they became Jehovah’s Witnesses (Z= −1.974; p = 0.048). Jehovah’s Witnesses are a group characterised by a high degree of consistency when it comes to religiosity, attitudes regarding health and disease and health behaviours. This means that they follow the teachings of their religion with regard to health issues. Knowledge about the association between religiosity and health behaviours is important to provide effective health education, health promotion and development of health prevention policy, specifically when dealing with more religious groups of clients.