Background: Despite national disease management plans optimal asthma management remains a challenge in Australia. Community pharmacists are ideally placed to implement new strategies that aim to ensure asthma care meets current standards of best practice. In this study, the impact of a pharmacy asthma care program (PACP) on asthma control was assessed using a multi-site, randomised intervention versus control, repeated measures study design. Methods: Fifty Australian pharmacies were randomised into two groups: intervention pharmacies implemented the PACP (an ongoing cycle of assessment, goal setting, monitoring and review) to 191 patients over six months, while control pharmacies gave their usual care to 205 control patients. Both groups administered questionnaires and conducted spirometry testing at baseline and six months later. The main outcome measure was asthma severity/control status. Results: Ninety-one percent (186/205) of control patients and 86% (165/191) of intervention patients completed the study. The intervention resulted in improved asthma control: patients receiving the intervention were 2.7 times more likely to improve from ‘severe’ to ‘not severe’ than the control patients (OR=2.68, 95% CI=1.64, 4.37, p<0.001). The intervention also resulted in improved adherence to preventer medication (OR=1.89, 95% CI 1.08 to 3.30, p=0.03), decreased mean daily dose of reliever medication (difference -149.11mcg, 95% CI -283.87 to -14.36, p=0.03), a shift in medication profile from reliever only to a combination of preventer, reliever ± LABA (OR=3.80, 95% CI 1.40 to 10.32, p=0.01) and improved scores on risk of non-adherence (difference -0.44, 95% CI -0.69 to -0.18, p=0.04), quality of life (difference -0.23, 95% CI -0.46 to 0.00, p=0.05), asthma knowledge (difference 1.18, 95% CI 0.73 to 1.63, p<0.01), and perceived control of asthma questionnaires (difference -1.39, 95% CI -2.44 to -0.35, p<0.01). No significant change in spirometry measures occurred in either group.Conclusions: A pharmacist delivered asthma care program based on national guidelines improved asthma control. The sustainability and implementation of the program within the health care system remains to be investigated.