Amartya Sen introduced the Capability approach in 1979 as a more appropriate theory of justice than existing theories in moral philosophy. The main features of the Capabilities approach and its operationalisation in the context of poverty analysis are discussed in this paper. The three broad approaches to operationalisation i.e. evaluation in the functionings space, in the functionings space combined with the income space, or the income space supplemented by functionings information, are outlined. The paper restricts itself to the functionings space and therefore concentrates on the first of these. Issues pertaining to the assessment of capabilities as well as assessment restricted to the chosen functioning vector, selection of capabilities/functionings to be assessed, and possible procedures that may be used for inter-personal comparisons are discussed. Concentrating on operationalisation in developing countries, lists of 'basic' capabilities developed by different researchers, using differing methodologies are compared. The comparison indicates that capabilities related to health, nutrition and education consistently appear in all the lists, despite the different criteria for inclusion, reflecting their importance for any capabilities based investigation of poverty.