This paper presents the latest developments in the Fonnal Methods in Confonnance Testing (FMCT) project of ITU and ISO. The project has been initiated to study the role of fonnal description techniques in the confonnance testing process. The goal is to develop a standard that defines the meaning of confonnance in the context of FDTs. A general framework which has been developed in the FMCT project will be presented.Recently, more and more specifications in the communications world are being made by use of a fonnal description technique (FDT). This makes it necessary to define the meaning of confonnance in this fonnal context. ISO and ITU-T started another joint project around 1989, called project 1.21.54 in ISO and question 8/10 in ITU-T. This new effort should result in a standard on "Fonnal Methods in Confonnance Testing (FMCT)" [3]. The current planing of the project extends to May 1997. At this date the pUblication of an International Standard in ISO and the respective standard in ITU-T is desirable. This means that there needs to be a Committee Draft around middle of 1995 and a Draft International Standard around 1996. Two main meetings of the project are planned per year, but there may be additional meetings in the subgroups.Given a fonnal specification, how can one find out whether an implementation confonns to this specification?The motivation of this activity is the existence of fonnally described standards and therefore the need to define the meaning of confonnance with respect to fonnal specifications.T. Mizuno et al. (eds.), Protocol Test Systems