Patients' health literacy is increasingly recognized as a critical factor affecting health communication and outcomes. We performed this study to assess the levels of health literacy by using Rapid Estimate of Adult Literacy in Medicine (REALM) and Newest Vital Sign (NVS) instruments. Patients (n = 456) at a family medicine clinic completed in-person interviews, REALM and NVS tests which were translated into the Turkish language by translation-back translation process. Additional questions regarding demographic characteristics were also collected. The mean scores (mean +/- standard error) for REALM and NVS were 60.2 +/- 90.32 and 2.60 +/- 0.08, respectively. The REALM test scores showed that 2.7% had inadequate (less than or equal to 6th grade), 38.6% marginal (7th to 8th grade) and 58.7% (greater than or equal to 9th grade) adequate health literacy. The NVS test score revealed a proportion of 28.1% had adequate health literacy. Educational attainment was the most important demographic characteristic found to be related to the health literacy. Reading and vocabulary skills were better than numerical capabilities. Female, primary school educated and poor economic condition participants and those who were older had the lowest scores in both the tests.