Social support is supposed to have a beneficial effect on the health and wellbeing of people. It is a central concept in the 'EUropean Research on Incapacitating DIseaes and Social Support' (EURIDISS). In general, two main distinctions concerning social support are made in the literature, providing four basic dimensions or types of social support: a social-emotional vs an instrumental type of social support, and a 'crisis' or 'problem-oriented' vs 'everyday' or 'daily' type of social support. Based on these types of social support, a series of items were formulated to measure actual supportive interactions or exchanges of resources. The items were spread over five scales. The social-emotional type of social support comprised three scales; daily emotional support; problem-oriented emotional support; and social companionship, while the instrumental type of social support consisted of two scales: the daily instrumental support and the problem-oriented instrumental support. Together, these items and scales constitute the so-called 'Social Support Questionnaire for Transactions' (SSQT). The main objective of this paper is to investigate whether one and the same instrument, i.e. the SSQT, allows for meaningful comparisons between patients with rheumatoid arthritis from different countries. More specifically, the dimensionality and invariance of the dimensions across countries of the SSQT are explored. To this end, patients from four different European countries (France, Norway. The Netherlands and Sweden) were asked to fill in the SSQT. The analysis of the data using principal component analysis (PCA) and simultaneous component analysis (SCA), did yield the intended scales, although the internal consistency of one of them, the daily instrumental support scale, is questionable. It is concluded that, particularly in the area of social-emotional support, the SSQT is a useful instrument for international comparative research.