Achieving universal health insurance coverage is a goal for many developing countries. Even when universal health insurance programmes are in place, there are significant barriers to reaching the lowest socio-economic groups such as a lack of awareness of the programmes or knowledge of the benefits to participating in the insurance market. Conditional cash transfer (CCT) programmes can encourage participation through mandatory health education classes, increased contact with the health care system and cash payments to reduce costs of participating in the insurance market. This work aims to explore if participation in a CCT programme in Mexico, Oportunidades, is significantly associated with self-reported enrolment in a public health insurance programme. It found that participation in the Oportunidades programme is associated with a 25% higher likelihood of being actively aware of enrolment in Seguro Popular, a public health insurance scheme for the lowest socio-economic groups. Participation in the Oportunidades CCT programme is positively associated with awareness of enrolment in public health insurance. CCT programmes may be used to promote participation of the lowest socio-economic groups in universal public health insurance systems. This is crucial to achieving universal health insurance coverage in developing countries.