Longitudinal research helps to clarify changing needs and the timing of treatments and referral but is hampered by poor recruitment and retention of participants. We explored, using semi-structured interviews in a cross-sectional design, the views and preferences of patients with advanced cancer on taking part in planned longitudinal questionnaire-based research studies. Patients with advanced lung and colorectal cancer were recruited from outpatient clinics in a London hospital. Semi-structured interviews were undertaken to explore their views about taking part in a specific future questionnaire study and their preferences regarding format. In all, 20 of 47 patients initially identified were recruited. Their preferences for the planned questionnaire study were for face-to-face interviews undertaken at home from late morning onwards with recontact at a mean of 6 weeks. Fluctuating symptom control needs could result in unexpected admission to or discharge from hospital. Developing flexible and responsive recruitment procedures is vital to retain patient participation as more than one contact might be required to successfully conclude an interview.