We investigated the quality of life (QoL) of newly diagnosed persons with cancer aged 65 years at baseline and 3 months after, in relation to age, contact with the healthcare system, activities of daily living, hope, social network and support using the European Organization for Research and Treatment of Cancer QLQ-C30, Katz ADL, Nowotny's Hope Scale, and the Interview Schedule for Social Interaction. Participation at baseline was 101 (74 women, 27 men), and after 3 months was 85(66 women, 19 men). Fatigue was the most reported symptom both at baseline and 3 months after. No significant changes were found in QoL from baseline to 3 months after, whereas perceived social network and 2 subscales ("confidence" and "comes from within") in Nowotny's Hope Scale deteriorated significantly. Dependency, reduced economic ability, and low level of hope were significantly associated with low QoL at the 3-month follow-up. From the perspective of QoL, nurses need to address more specifically the most vulnerable elderly cancer patients: those who are dependent in instrumental activities of daily living, those who perceive reduced economic ability, and those who need assistance to discover new strategies to strengthen hope.