The multidimensional concepts of “quality of employment”, advocated by the European Commission, and “decent work,” promoted by the International Labour Office (ILO), are not easy to address. The studies on these topics are not new but their number and scope have increased considerably in the past dozen years or so. From a survey of this literature, particularly of the comparative analyses at European level, we show the difficulties involved in defining the various dimensions of the concept of quality of employment and work, and in measuring them by means of indicators. We conclude by showing how these choices of definition and measurement can produce analyses that yield different but sometimes complementary conclusions. Our article addresses the delicate question of whether it is legitimate to seek to calculate a synthetic (or composite) indicator of quality of employment, which is supposed to summarize all the information available and thus make it easier to interpret. After examining its advantages and drawbacks in detail, the authors are relatively cautious about the exclusive use of such an index. The studies that seem most conducive to a proper assessment of quality of employment are those that adopt a broad, multidimensional approach to quality of employment and work. Such studies link this perspective with the institutionalist literature on capitalist systems and employment systems, and with approaches combining contributions from various disciplines.