Objective To analyse the role and meaning of health information in individuals' experiences with either breast, colorectal or prostate cancer in order to better understand unmet information needs of people with a cancer diagnosis. Design This is a secondary analysis of data from a qualitative interview study including narrative interviews and maximum variation sampling. A thematic analysis was conducted, followed by an in-depth analysis based on the principles of grounded theory. Setting Interviewees were sought across Germany through self-help organisations, primary care clinics, rehabilitation facilities, physicians and other healthcare professionals to develop cancer modules for the website kr ankheitserfahrungen.de (illness experiences.de). Participants Women with a diagnosis of breast cancer, individuals with a diagnosis of colorectal cancer and men with a diagnosis of prostate cancer. Results The meaning and role of information in the illness experiences were clearly associated with gaining control in a seemingly uncontrollable situation in which others people, the disease take over. Four categories characterise the ways in which information helped interviewees to regain a sense of control following a diagnosis of cancer: 'becoming confident in one's treatment decision', 'taking responsibility for one's situation', 'understanding the consequences of the disease and treatment for one's life', and 'dealing with fear'. There was, however, always a fine line between information seeking and becoming overwhelmed by information. Conclusions Information needs to be understood as a management tool for handling the disease and its (potential) consequences. Patients' unmet needs for information might not be easily solved by a simple increase in the amount of information because emotional support and respect for patient autonomy might also play a role. The evaluation of one's own information behaviour and the information received is closely linked to how the illness unfolds. This makes it challenging to document unmet information needs and satisfaction with information independent of an individual's illness trajectory over time.