Urinary tract infection (UTI) is a prevalent infection among the elderly population, often culminating in more severe and life-threatening complications. The prevalence of diabetes among elderly individuals is markedly on the rise, with UTI emerging as the most prevalent infectious ailment in this diabetic cohort. This study aims to ascertain the influence of theory-based education on promoting UTI prevention behaviours among elderly diabetic women. In this experimental study, 100 elderly women with diabetes who sought care at comprehensive health service centres in Miandoab City between January and May 2022 were assessed. Multistage random sampling was employed, and an educational intervention was designed according to the health belief model (HBM) constructs. Data collected before and one month after the educational intervention were analysed with a validated and reliable researcher-designed questionnaire. The participants had a mean age of 62.30 ±7.63 years. There was significant disparity between the experimental and control groups concerning the mean scores for knowledge, HBM constructs, and behaviour, with adjustments made for baseline differences. In essence, the intervention had significant affects, resulting in heightened levels of knowledge, improvements in HBM constructs, and more favourable behavioural changes. The effect size was moderate for perceived benefits and severity, while it was large for other variables (p < 0.05). The research findings validate the effectiveness of an intervention grounded in HBM for fostering UTI prevention behaviours among elderly diabetic women. Consequently, such an approach is recommended for enhancing the overall health of elderly diabetic women.