PURPOSE: Oral anticancer therapies have an important place in the therapeutic arsenal, but factors influencing adherence to oral treatment are poorly documented in oncology. The objective of this study was to assess the impact of anxio-depressive symptoms and cognitive functioning on oral medication adherence. METHODS: This prospective study included cancer patients initiating a first oral therapy. Before initiation of treatment, an assessment of depression, anxiety, and cognition was performed. Using self-report questionnaires, we collected information on socio-demographic conditions and the non-adherence at 1 (M1) and 3 months (M3) after the beginning of treatment. RESULTS: Among 129 patients enrolled, median age was 70 years and 81% of patients were treated for metastatic cancer. Before initiating treatment, 16% and 8% of patients presented respectively depression and anxiety symptoms. Global cognitive impairment was observed in 51% of patients. Ten percent of the patients were non-adherent at M1 and 13% at M3. Depression was strongly associated with non-adherence at M1 (P = 0.046) and M3 (P = 0.014), but not anxiety. Non-adherence was associated with lower working memory (P = 0.037) and digit memory (P = 0.018) at M1 and short-term memory (P = 0.04) at M3. Patients with more than eight co-medications were more often non-adherents (P = 0.055). CONCLUSIONS: Non-adherence to oral anticancer therapies was mainly associated to depression. Focusing on depressive symptoms before initiation of oral anticancer therapy could help to identify patient profiles more likely to fail self-management. Working memory, digit memory, and short-term memory also seem to play a role in non-adherence. Further studies should include a more specific population, especially according to age.