This work is part of a collaborative study involving research teams in Canada and Mexico. The general objective is to describe the process of cultural adaptation and semantic validation of three measuring instruments on stigma and mental illness in Mexico City. Based on the criteria of understanding, acceptance, relevance and semantic integrity, the following instruments were adapted: the Internalized Stigma Inventory (ISMI), the Mental Illness Opinion Questionnaire (IMO) and the Devaluation Perception and Discrimination Scale against Mental Illness (DDS). For this, four individual interviews were conducted and four in a group with 37 informants from various sectors (health personnel, people diagnosed with severe mental disorders, family members and the general population). Finally, a content analysis of the information obtained was performed. The adapted instruments were culturally appropriate for the population of the different groups studied in Mexico. Adapted versions will be useful for benchmarking with other regions. The scope and limitations of the semantic equivalence process in cross-cultural research are analyzed.