This is the third in a series of three papers on cognitive therapy formulation with older people. The aims of this paper are to identify barriers to collaborative conceptualization, and to summarize useful strategies for overcoming these barriers. Obstacles to collaborative conceptualization with older clients have previously been thought of as a consequence of age-related skills deficits. In this paper we focus instead on the barriers created by therapistand client-held prejudicial beliefs. A social cognitive perspective is used to conceptualize stereotypical prejudices. Strategies are described for challenging or reframing prejudicial beliefs, and addressing the mechanisms that perpetuate these beliefs.