The importance of gaining further knowledge as to the health-related needs and expectations of individuals, as well as of the factors involved in the effectiveness of health care activities, particularly of the professionals proper, make it possible to anticipate a boom in Qualitative Research in fields such as Public Health and Health Service Research. Such an increase should go hand in hand with a progressive improvement in the quality of the outcomes of research, to which end tools for assessing said quality are required. However, the epistemological implications of the qualitative focus contribute to the setting of the bounds of these tolls having been a source of controversy at both the conceptual level as well as with regard to the methods and techniques to be employed, although without hardly any involvement on the part of the health sciences in our country. This article provides a brief review of the main points of reference of said debate and, after stressing the importance of the theoretical development and of precision in practice, as well as the function of the guides with regard thereto, the epistemological adaptation, relevance, validity and reflexivity as possible basic criteria for the assessment of the quality of Qualitative Research are proposed.