BACKGROUND: Diabetes and hypertension are key risk factors for coronary heart disease. Prevalence of both conditions is socio-economically patterned. Awareness of presence of the conditions may influence risk behaviour and use of preventative services. Our aim was to examine whether there were socio-economic differences in awareness of hypertension and diabetes in a UK population. METHOD: Data from the Scottish Health Survey was used to compare self-reported awareness of hypertension and diabetes amongst those found on examination to have these conditions, by socioeconomic position (SEP) (measured by occupation, education and income). Odds ratios of self-reported awareness against presence, and the sensitivity, specificity and predictive value of self-reporting as a measure of the presence of the condition, were calculated. RESULTS: Presence and self-reported awareness of both conditions increased as SEP decreased, on most measures. There was only one significant difference in awareness by SEP once other factors had been taken into account. Sensitivity showed that those in the most disadvantaged groups were most likely to self-report awareness of their hypertension, and specificity showed that those in the least disadvantaged groups were most likely to self-report awareness of its absence. There were few differences of note for diabetes. CONCLUSION: We found no consistent pattern in the associations between SEP and the presence and self-reported awareness of hypertension and diabetes amongst those with these conditions. Without evidence of differences, it is important that universal approaches continue to be applied to the identification and management of those at risk of these and other conditions that underpin cardiovascular disease.