The aim of the present paper is to present the initial phases of the development of the Spanish version of the "World Health Organization Disablement Assessment Schedule II" WHO-DAS-II and also to describe the quantitative and qualitative methodological strategies used in the elaboration process of an instrument: i) compatible with the new International Classification of Functioning and Disability -ICIDH-2- of the World Health Organisation; ii) with criteria of cross-cultural applicability and; iii) to allow us to assess the disability in all its dimensions.