The study involved quantitative methods to assess the relationship between knowledge about cancer related symptoms and help seeking behaviour and qualitative methods to explore the role of patient's beliefs about cancer in explaining the gap between knowledge and behaviour. Patients (288) (response rate 72%) from one urban general practice completed a questionnaire consisting of 25 symptoms which they rated for whether they were cancer symptoms (knowledge) and whether the symptoms would prompt them to visit the doctor (hypothetical help seeking behaviour). Twenty patients were then selected who represented a range of knowledge levels and help seeking behaviour and interviewed about their beliefs about cancer. The results showed that the majority of patients had fair knowledge and appropriate help seeking behaviour and indicated a significant association between these variables. However, this relationship was not absolute and although significant the correlation was low. Accordingly, although the subjects knew which symptoms were indicative of cancer, this knowledge was not entirely predictive of their help seeking behaviour. The interviews provided insights into the beliefs which may explain the knowledge/behaviour gap. In particular, analysis of the interviews indicated that the interviewees represented cancer in terms of feelings of fear and death, that they described the process of symptom recognition as involving a fear of finding out the truth, they regarded screening programmes as something to be avoided and understood the causes of cancer either in terms of personal behaviour and internal causes which may result in recriminations or external causes which were beyond their control. The results are discussed in terms of the role of beliefs in mediating the association between knowledge and behaviour and the possible implications for developing educational programmes.