The silver–calcium system has been reinvestigated over the whole composition range by thermal analysis, X-ray diffraction, and metallography. A novel technique has been used to prepare and examine these reactive alloys. In the course of this project four intermetallic compounds have been observed for the first time; while two others, viz., Ag2Ca and AgCa, which were reported before by others, have been confirmed. Three of the new compounds are: Ag8Ca3, Ag3Ca5, and AgCa3, while the fourth was not isolated or examined in detail. Two other compounds which were described in earlier work as Ag4Ca and Ag3Ca, have been found to be Ag9Ca2 and Ag7Ca2, respectively. Major modifications have been made in the liquidus curve and possible reactions in the solid state are indicated.