This study focuses on the qualitative research interview, an essential tool frequently used in the human and social sciences, conducted with children having communication disorders. Two distinct populations are addressed--children with intellectual disability and deaf children without related disabilities--with the aim of identifying the main methodological issues and proposing arrangements to encourage them to express themselves during research interviews. It transpires that the common features between interviews conducted with these two populations relate to the need to get to know the child and his or her environment, resort to visual aids and manage as best one can the investigative relation. The differences between these two populations hinge around both communication (the difficulties experienced by the children in understanding and/or expression) and how the interview is conducted (social desirability shown by the children and strategies in conducting the interview by the researcher).