OBJECTIVES: Peoples’ beliefs towards health and illness play an important role in health seeking behavior. Cancer patients’ beliefs regarding cancer have been reported to be important factors affecting screening and treatment seeking behavior. This study was aimed to evaluate cancer patients’ beliefs about cancer and its causes. METHODS: A qualitative research approach was adapted. After obtaining institutional ethical approval, patients with different types and stages of cancer from the three major ethnic groups in Malaysia were purposively selected to participate in the interview. Twenty patients whom had consented were interviewed using a semi-structured interview guide. After conducting 18 interviews the saturation point was reached and no more themes were emerged from the subsequent interviews. All interviews were audiotaped, transcribed verbatim and translated into English for thematic content analysis.  RESULTS: The emergent themes were as follows: unknown reasons, internal factors, environmental perceptions, and spiritual attributions. In this preliminary investigation cancer patients described cancer as a disease present in every human being and it may become visible during the course of life. Genetic predisposition, female gender and hematological factors were reported to be some of the internal factors.  Unhealthy life style habits such as smoking, high consumption of red meat, and pesticides in foods were some of the environmental factors that were described. Among those who claimed to have healthy habits prior to the illness, there was a rejection of the notion that unhealthy life style was a cause. A strong spiritual connection was found as many patients described their cancer diagnosis as 'God’s will.' CONCLUSIONS: This exploratory investigation suggests that cancer patients’ understanding about cancer is complex in nature. The findings may help health care providers remove myths about cancer and reassure patients during the treatment decision making process. It may also help in improving patients’ compliance towards the proven cancer therapies.