Health literacy is how well the patients are able to attain, deal with, and understand basic health information. This is particularly important when it comes to comprehending prescribed medication instructions. To improve the communication strategies for health-care professionals during patient counseling, our study aimed to assess the influence of health literacy and medication adherence in older patients. The objectives of the study were to evaluate associations that occur between the level of health literacy and medication adherence. This study used a convenience sampling method of females (older than 60 years) attending the diabetic clinic in two hospital settings (N = 524). All study participants filled three validated questionnaires: these were the Literacy Assessment for Diabetes, the Diabetes Numeracy Test, and a modified Brief Adherence Rating Scale. To assess the spectrum of health literacy differences, we used χ2 analysis and linear regression analysis. Individuals with adequate health literacy were more likely to remember to take their medications compared with those with inadequate health literacy, χ2(4) = 11.6, p =.04. Adequate literacy level study participants were more likely to not change the dose of their medications without medical advice (12.3%) compared with those individuals with inadequate health literacy (2.8%), χ2(4) = 11.13, p =.03. The results in our study suggest that health-care professionals should focus on appropriate communication attuned to the assessment of health literacy levels particularly in older female patients when discussing medication instructions. © The Author(s) 2019.