To measure the level of functional health literacy (FHL) in an Australian population, and to explore the level of risk associated with level of FHL.

Cross-sectional, random population survey administered to 2824 South Australians aged ≥ 15 years, September – October 2008.

Newest Vital Sign as a measure of FHL, self-reported general health status, and use of health services.

24% of respondents were at risk of limited FHL, and 21% had a high likelihood of inadequate FHL; this increased with age (≥ 65 years, 50% v 25–44 years, 11%). In multiple logistic regression models, a high likelihood of inadequate FHL was significantly more common among those with lower education (left school ≤ 15 years of age, odds ratio [OR], 8.1; 95% CI, 4.8–13.6); with lower annual income (< $20 000, OR, 4.1; 95% CI, 2.3–7.4); who were born in countries other than Australia, New Zealand, the United Kingdom and Ireland; and with poorer health status (OR, 1.6; 95% CI, 1.2–2.2). Inadequate FHL was significantly less common among females (OR, 0.6; 95% CI, 0.5–0.8). People with inadequate or at-risk FHL were significantly more likely to report having diabetes, cardiac disease or stroke, and significantly less likely to have recently attended a doctor. Respondents aged ≥ 65 years with inadequate FHL were more likely to have been admitted to hospital (OR, 2.2; 95% CI, 1.1–4.5).

Many Australians are likely to have limited health literacy, and this is a risk to effective health care delivery and health improvement across the community.