BACKGROUND: Latin America ranks among the regions with the highest level of intake of sugary beverages in the world. Innovative strategies to reduce the consumption of sugary drinks are necessary. PURPOSE: Evaluate the effect of a one-off priest-led intervention on the choice and preference of soda beverages. METHODS: We conducted a pragmatic cluster-randomized trial in Catholic parishes, paired by number of attendees, in Chimbote, Peru between March and June of 2017. The priest-led intervention, a short message about the importance of protecting one's health, was delivered during the mass. The primary outcome was the proportion of individuals that choose a bottle of soda instead of a bottle of water immediately after the service. Cluster-level estimates were used to compare primary and secondary outcomes between intervention and control groups utilizing nonparametric tests. RESULTS: Six parishes were allocated to control and six to the intervention group. The proportion of soda selection at baseline was 60% in the intervention and control groups, and ranged from 56.3% to 63.8% in Week 1, and from 62.7% to 68.2% in Week 3. The proportion of mass attendees choosing water over soda was better in the priest-led intervention group: 8.2% higher at Week 1 (95% confidence interval 1.7%-14.6%, p = .03), and 6.2% higher at 3 weeks after baseline (p = .15). CONCLUSIONS: This study supports the proof-of-concept that a brief priest-led intervention can decrease sugary drink choice. CLINICAL TRIAL INFORMATION: ISRCTN, ISRCTN24676734. Registered 25 April 2017, https://www.isrctn.com/ISRCTN24676734.