Cognitive-behaviour therapy was used in an attempt to modify the delusional beliefs of six clients with psychosis. It was hypothesised that the empirically vindicated "belief modification" (BM) package (Chadwick & Lowe, 1994) would benefit from being augmented by a "motivation modification" (MM) package which focuses directly on the client's motivation to change. Using single-case methodology, these two cognitive therapies were employed in different phases over two conditions. Three clients received MM therapy before BM therapy, and three clients received BM therapy before MM therapy. Belief conviction was reduced in four of the six participants, whilst two participants demonstrated no change in belief conviction. The results tentatively indicate that clients receiving MM before BM demonstrated a greater reduction in belief conviction than clients receiving BM before MM. The implications of these results are discussed, and it is argued that motivational issues play an important role in the maintenance of delusions. Future research directions are forwarded for deriving useful models of underlying processes involved in using motivation modification as an adjunct to belief modification