Background Socially disadvantaged men are more likely to binge drink frequently and to experience high levels of alcohol-related harm. Objectives To test the effectiveness and cost-effectiveness of a text message intervention in reducing the frequency of binge drinking among disadvantaged men. Study design A four-centre, parallel-group, pragmatic, individually randomised controlled trial was conducted. Randomisation was carried out using a secure remote web-based system. It was stratified by participating centre and recruitment method and restricted using block sizes of randomly varying lengths. Setting The study was conducted in the community. Members of the public helped to develop the study methods. Participants Participants were men aged 25–44 years who had ≥ 2 episodes of binge drinking (> 8 units of alcohol in a single session) in the preceding 28 days. Men were recruited from areas of high deprivation. Interventions An empirically and theoretically based text message intervention was delivered by 112 interactive text messages over a 12-week period. The control group received an attentional control comprising 89 text messages on general health. Primary outcome measure The primary outcome measure was the proportion of men consuming > 8 units of alcohol on ≥ 3 occasions (in the previous 28 days) at 12 months post intervention. Results The recruitment target of 798 was exceeded and 825 men were randomised. Retention was high and similar in the intervention (84.9%) and control (86.5%) groups. Most men in the intervention group engaged enthusiastically with the text messages: almost all (92%) replied to text messages and over two-thirds (67%) replied more than 10 times. The intervention was estimated to have had a modest, statistically non-significant effect on the primary outcome at the 12-month follow-up [odds ratio 0.79, 95% confidence interval (CI) 0.57 to 1.08]. This corresponds to a net reduction of 5.7% in regular binge drinking. Five secondary outcomes showed small non-significant and inconsistent effects on alcohol consumption, with one suggesting a positive effect and four suggesting an adverse effect. Both the short- and the long-term cost per quality-adjusted life-year (QALY) analysis suggested that the brief intervention was dominated by a ‘do-nothing’ option. The intervention’s impacts on patterns of alcohol consumption, QALYs and downstream costs were inconsistent and uncertain. Limitations The study used an active control that, combined with the recruitment procedures and baseline assessments, could have biased the treatment effect towards the null. The measurement of alcohol consumption relied on self-reported drinking. Conclusions The trial has demonstrated that it is possible to recruit and retain large numbers of socially disadvantaged men in a research study. The text messages delivered a complex theoretically and empirically based intervention that fostered enthusiastic engagement with the key components of the behaviour change sequence. The intervention produced a modest, statistically non-significant effect on the primary outcome, with wide CIs. Further research is needed to reduce uncertainty about the treatment effect. The methods developed for this study provide a platform for the design and testing of interventions to reduce inequalities in health. Future work A future trial could reduce the uncertainty around the treatment effect of the intervention. Trial registration Current Controlled Trials ISRCTN07695192. Funding This study was funded by the National Institute for Health Research (NIHR) Public Health Research programme and will be published in full in Public Health Research; Vol. 6, No. 6. See NIHR Journals Library website for further information.