AimWe aimed to examine the advertising and marketing of breast milk substitutes (BMS) through the internet, social media and television in Mexico.MethodsWe recorded the programming of four main TV channels at peak times to identify BMS advertisements. In addition, we identified the main BMS products and companies present on the internet, as well as related home pages and social networks (Facebook, Twitter and YouTube). After that, we examined current BMS' marketing practices using the International Code of Marketing of Breast‐milk Substitutes (‘the Code’) as a framework for ethical marketing. Qualitative and statistical analyses are presented.ResultsBMS manufacturers have a presence on television, social media and the internet. Violations of the Code, as well as promotional practices unforeseen by the Code, were identified in all the studied media. These include text and images idealising the use of BMS, as well as mechanisms for boosting sales and making contact with consumers.ConclusionsThe Mexican population is exposed to BMS advertisements that breach the Code on the internet, on social networks and on television. Emerging challenges related to the use of electronic means to market BMS may call for new strategies for monitoring and enforcing the Code through local regulations.