The objectives of this study were to identify the prevalence of psychosocial need, and the contributory factors to need, among cancer patients, using a descriptive cross-sectional questionnaire survey of adult cancer patients. The participants were 1,000 patients from four hospitals in the north west of England with the following characteristics: tumour type (breast, colorectal, lymphoma, lung), being 1 month from a 'critical moment' in the cancer journey (i.e. (i) diagnosis, (ii) end of first treatment, (iii) recurrence, (iv) move from active treatment to palliative care), and aged over 18 years. The main outcome measure was a psychosocial needs inventory comprising seven needs categories (48 need items). A sample of 402 was achieved (40% response rate). Psychosocial needs relating to the need categories 'health professionals', 'information' and 'support networks' are commonly expressed and strongly felt by cancer patients. Needs relating to 'identity', 'emotional and spiritual' issues and 'practical' issues are less commonly expressed but are also strongly felt. Particular needs are related to tumour type, illness 'critical moment', age, gender, health status, socioeconomic and other social factors. This information should increase awareness among cancer care professionals about a range of psychosocial needs and may help them target particular patient groups for particular support interventions.