A test and a rating method have been developed to assess the hot-tearing susceptibility of cast copper alloys. Thirteen alloys were rated, and, while the limitations of individual hot-tear tests are well known, it is considered that such a rating should serve as a general guide to enable foundrymen to select alloys with the best hot-tear resistance where this may be important in a particular casting design. The probable process by which these alloys - particularly tin bronzes - solidify is tentatively related to the hot-tearing mechanism, which is discussed in general terms. From this type of study, it may be possible to design alloys of improved hot-tear resistance, or to anticipate hot-tearing difficulties in new alloys designed from other considerations.