Introduction: Carers of patients with lung cancer often have a short time to access the support they require. The Macmillan Carers Project (MCP) was set up to provide non-clinical social support targeted in the community to the carers of patients with lung cancer and this study describes its evaluation. Methods: Prospective case study using interviews with the carers, project workers and health and social care professionals to obtain qualitative data for thematic analysis. 81 patients’ carers received support from the MCP; 20 carers, 2 MCP workers and their manager and 10 other professionals (chest consultant physician, lung cancer clinical nurse specialist, GP, four Macmillan nurses, hospice social worker and two community social workers) were interviewed. Results: Patients were predominantly male (62%), mean age 71 years and carers were predominantly female (70%) mean age 63 years. Carers identified the MCP as providing emotional support, more time, practical help, financial advice, information and back-up for a myriad of problems. Although there was some overlap with other services, the MCP was valued by carers and professionals as filling a gap in social care. Conclusions: The unique aspect of this study was support targeted to the carers of a single cancer site (lung) rather than generic cancer support. As lung cancer may progress rapidly, patients and their carers have a short time to gather new information, access services and adjust to their new circumstances and roles. By focusing on the needs of carers from the time of lung cancer diagnosis, we have shown that the MCP was a valued additional service, well received by carers, patients and professionals.