Background Guidelines for management of hypertension and lipids recommend using cardiovascular absolute risk (CVAR) to manage patients. This randomized controlled trial investigated the impact of CVAR assessment in family practice on management of cardiovascular risk, including prescription of antihypertensive and lipid-lowering medication. Methods A cluster randomized controlled trial was conducted from 2008 to 2010 in Sydney, Australia. Family practices were randomized, and patients aged 45 to 69 years were invited to participate. Intervention family physicians (FP) were trained in use of CVAR, provided with an electronic CVAR calculator, and assessed their patients' absolute risk in a dedicated consultation. Control practice patients received a general health check. Primary outcome analyzed was the proportion of patients in each group on antihypertensive and/or lipid-lowering medication at 12 months. Multilevel logistic regression was performed to explore variables influencing changes in pharmacologic therapy. Results The study recruited 36 FPs from 34 practices and 1,074 patients, of which 906 (84.4%) completed 12-month follow-up. At 12 months, there was no significant difference between the intervention and control groups in proportion of patients on antihypertensives (31.2% vs 34.3%, P =.31), but control group patients were more likely to be on lipid-lowering medications (30.2% vs 22.7%, P =.01). After multilevel analysis, this difference was not present. Intensification or reduction of pharmacologic therapy was associated with meeting treatment targets for blood pressure and lipids but not with the CVAR or intervention group. Conclusions Single-risk factor management remains a strong influence on FP prescribing practices. Shifting to an approach based on CVAR will require more intensive intervention.