Molecular pathological tests are performed on stored tumour material in order to identify individuals with hereditary non-polyposis colorectal cancer. We have previously identified that there is widespread use of this testing and now describe what counselling occurs prior to testing and the approaches in seeking consent. A respondent from every cancer genetic centre in UK offering microsatellite instability and/or immunohistochemistry testing (n= 20, response rate = 100%) was interviewed in order to ascertain pre-test counselling and consent protocols. Individuals providing consent are not always seen in person prior to providing consent but few services had supporting written information. Nine (of 19) consent forms documented consent to perform genetic testing, while the majority (14/19) sought consent to release pathology samples to the genetic service. Less than half of the services routinely seek consent to test samples from a deceased individual. Concerns were raised about spousal consent when the implications of results are for blood relatives. The differences identified between genetic counselling for testing of tumour tissue and for germ-line genetic testing suggest that counselling protocols specific for somatic testing should be developed. The results are discussed in the context of a changing legal environment and anticipated growing demand for testing.