PURPOSE: Studies examining longitudinal associations between socioeconomic factors and quality of life (QoL) in cancer patients are rare. This study investigates changes in QoL over a 6-month period. METHODS: Four hundred forty-two cancer patients (mean age 64, SD = 11, 70% male) completed standardized questionnaires at the beginning (t1) and end (t2) of their hospital stay and 3 (t3) and 6 months (t4) thereafter. QoL was assessed with the EORTC QLQ-C30 core questionnaire. Mixed effect models were employed to analyze individual changes in QoL in relation to socioeconomic status (education, income, job status) over the four timepoints. Age, sex, cohabitation, disease and treatment factors, and comorbidity were included as covariates in the models. RESULTS: Income was a predictive factor for QoL. Patients with a low income had 8.8 percentage points (PP) lower physical, 4.9 PP lower emotional, and 11.4 PP lower role functioning. They also had 6.6 PP lower global QoL. Lower social functioning (6.2 PP) was found in patients with higher education or university degrees compared with those who were less educated or had not undergone an apprenticeship. Income also influenced trajectories of role functioning. There was no evidence that primary or secondary education and job type were related to QoL. CONCLUSIONS: The fact that income is negatively associated with many aspects of quality of life should be considered during and after treatment with a focus on patients with special needs.