Crosslinking of nitrile rubber (NBR) and poly(vinyl chloride) (PVC) can be accomplished separately using ethylenethiourea (ETU) with and without the presence of sulphur (S) respectively. ETU/S combination in appropriate doses brings about ready co-crosslinking of NBR and PVC in their blends. Comparative studies of the curing characteristics of some NBR-PVC blends and some important physical properties of the blend vulcanizates have been made using the test curative (ETU/S system) and a conventional curative (tetramethylthiuram disulphide (TMTD)/sulphur (S) system). The ETU/S curative system produces crosslinking effects which in some respects are comparable with, and in some other respects are even substantially better than, those produced by the conventional TMTD/S curative system, particularly with respect to consequential curing parameters and blend vulcanizate properties including morphological patterns and ageing behaviour. © 1992.