The study describes the initial phases of research aimed at developing a methodology for assessing awareness in cancer patients. A first sample of cancer patients (n = 36) was interviewed about their knowledge of the diagnosis and their perception of treatment goals and outcomes. Thirteen domains which refer both to cognitive and emotional areas were identified, and considered as content valid by a panel of six experts. A second sample of patients (n = 54) participated in a semi-structured interview developed to explore awareness by means of the domains identified. Seven patterns of awareness were identified, ranging from 'completely aware patient' to 'completely unaware patient'. Twenty of the 54 patients (37.0%) were completely aware, 19 (35.2%) were partially aware with defence mechanisms and 15 (27.8%) were not aware of their diagnosis. Patients from the National Cancer Institute were more frequently aware (54.3%) compared with the patients interviewed in the community hospitals (5.3%) (p < 0.001). A computerized content analysis allowed the identification of two main groups of patients on the basis of the content of the recorded interviews. This independent classification agreed with the classification of the patients performed by the psychologists, suggesting the validity of the procedure of awareness evaluation proposed in this study.