IntroductionMobile health may be an effective means of delivering customised individually directed health promotion interventions for cardiovascular disease (CVD) primary prevention. The aim of this study is to evaluate the effectiveness of a lifestyle-focused text messaging programme for primary CVD prevention.Methods and analysisSingle-blind randomised controlled trial with 6 months’ follow-up in 246 patients with moderate-high absolute cardiovascular risk and without coronary heart disease recruited from a rapid access cardiology clinic. Participants will be randomised to receive either usual care or TextMe2 (text message-based prevention programme). The TextMe2 programme provides support, motivation and education on five topics: diet, physical activity, smoking, general cardiovascular health and medication adherence, and is delivered in four text messages per week over 6 months. The primary outcome is change in the proportion of patients who have three or more of five key modifiable risk factors that are uncontrolled (low-density lipoprotein >2.0 mmol/L, systolic blood pressure >140 mm Hg, body mass index >24.9 kg/m², physical activity (less than the equivalent of 150 min of moderate intensity each week), current smoker). Secondary outcomes are changes in single biomedical risk factors, behavioural risk factors, quality of life, depression/anxiety scores, medication adherence, cardiovascular health literacy and hospital readmissions/representations. Analysis will be according to the intention-to-treat principle and full statistical analysis plan developed prior to data lock.Ethics and disseminationThis study has been approved by the Western Sydney Local Health District Human Research Ethics Committee at Westmead (AU/RED/HREC/17/WMEAD/186). Results will be presented at scientific meetings and published in peer-reviewed publications.Trial registration numberACTRN12618001153202.