Most UK genetics centres offering predictive testing for hereditary non-polyposis colorectal cancer (HNPCC) use an extended counselling protocol originally developed for Huntington's disease. Shortened counselling may be more appropriate in the context of treatable genetic conditions such as HNPCC. Twenty-six high-risk individuals were randomized to extended genetic counselling (two sessions of education and reflection held 1 month apart) or shortened genetic counselling (a single educational session) prior to HNPCC testing. Prospective questionnaires, interviews and transcripts of counselling sessions were analysed. Participants were unsure what to expect prior to genetic counselling and had already decided to undergo genetic testing. There was no evidence of psychological harm caused by shortened genetic counselling, with a high level of satisfaction with the counselling received in both groups. Reflective counselling occurred in both groups but was framed in terms of practical action and information. Participants expressed differing preferences for the level of information received. This exploratory study indicates that shortened genetic counselling may be an appropriate means of supporting decisions already made by individuals about HNPCC testing. However, participants would benefit from preparatory information to help them reflect on issues not previously considered, which can then be explored more fully as part of a tailored counselling approach.