The study addresses the spiritual dimension of care of non-terminally ill cancer patients by measuring their spiritual needs in association with indicators of quality of life (i.e., happiness, satisfaction with life, pain intensity, functional capacity) and personal and illness characteristics. A descriptive, cross-sectional survey included 227 patients with cancer. All patients that underwent treatment at a nursing and supportive treatment unit were interviewed face-to-face between January and November 2018. Regression models were used to control for gender, education, religiosity, pain intensity, functional capacity, life satisfaction and happiness. The non-terminally ill cancer patients experienced the exceptional importance of Inner Peace and Giving/Generativity and Forgiveness, while Religious and Existential needs were scored marginally lower, but nevertheless much higher as compared to patients with cancer from West-Europe. Correlation analysis revealed strong positive and in one case moderate interconnections among each of four spiritual needs, with the strongest association between Existential needs and the other three domains. Unmet Religious needs were positively associated with pain intensity and reduced physical capacity of patients, but less with life satisfaction. Pain intensity was the strongest predictor of cancer patients’ Existential, Inner Peace and Giving/Generativity and Forgiveness needs. This study provides the first empirical evidence about the spiritual needs of cancer patients' care in Lithuania. Findings will serve as the basis for specific strategies to enhance the holistic well-being of these patients. The insights into oncology patients’ unmet spiritual needs may be relevant to other Eastern European and former Soviet Union countries with similar developmental histories. •Cancer patients’ unmet spiritual needs have to be recognised, assessed and supported.•Religiosity has the strongest influence on cancer patient's Religious needs.•Patients’ pain intensity predicts their Existential needs, Inner Peace needs and Giving/Generativity needs.•The interdisciplinary team must include an expanded role for chaplains and spiritual advisors.