BACKGROUND: A topic of great concern in bioethics is the medical research conducted in poor countries sponsored by wealthy nations. Western drug companies increasingly view Latin America as a proper place for clinical research trials. The region combines a large population, modern medical facilities, and low per capita incomes. Participants from developing countries may have little or non alternative means of treatment other than that offered through clinical trials. Therefore, the provision of a valid informed consent is important. METHODS: To gain insight about some aspects of the informed consent procedure in a major cancer centre in Mexico, we conducted a three-step evaluation process: 1) a ten point multiple choice survey questionnaires, was used to explore some aspects of the patients' experiences during the informed consent process, 2) researchers' knowledge about specific aspects of the informed consent was evaluated in this study using survey questionnaires; and 3) the comprehensibility, readability and number of pages of the consent forms were analysed. The socioeconomic and educational level of the patients, were also considered. Results were reported using a numerical scale. RESULTS: Thirty five patients, 20 doctors, and 10 individuals working at the hospital agreed to participate in the study. Eighty three percent of the patients in the study were classified as living in poverty; education level was poor or non existent, and 31% of the patients were illiterate. The consent forms were difficult to understand according to 49% of the patients, most doctors agreed that the forms were not comprehensible to the patients. The average length of the IC documents analysed was 14 pages, and the readability average score was equivalent to 8th grade. CONCLUSION: The results presented in this work describe some relevant characteristics of the population seen at public health care institutions in Mexico. Poverty, limited or no education, and the complexity of the information provided to the patients may question the validity of the informed consent procedure in this group of patients.