BACKGROUND: Despite its public health significance, data about depression in general practice are often unavailable or incomplete. OBJECTIVE: To study half-year follow-up data on patients diagnosed by their GP with a new episode of mild or a first episode of moderate depression, specifically: (i) treatment continuation, (ii) remission and, in ongoing episodes, suicidal behaviour and inability to work and (iii) the match between treatments initiated and delivered as well as the determinants of actual delivery of non-pharmacological support initiated by the GP for patients with ongoing depression. METHODS: General practice-based data were collected on all patients aged ≥18 years who were diagnosed by their GP with a new episode of depression in Belgian sentinel general practices during 2008. RESULTS: Follow-up data were available for 900 of 1048 patients. Complete treatment dropout was found in 9%, treatment discontinuation in 40% and a GP visit ≤8 weeks preceding the follow-up in 51%. Of the latter 457 patients, 60% were still depressed. Among these, one suicide attempt was reported and 24% were unable to work for ≥1 month. While 91% of the patients who received psychoactive agents at diagnosis had actually taken them, and 62% of the referred patients actually received treatment from another caregiver, non-pharmacological support by the GP was delivered in only 43% of patients for whom it was initiated. CONCLUSIONS: Half a year after diagnosis, half of patients continue to visit their GP and 60% of those patients remain depressed. The delivery of non-pharmacological GP support takes place for less than half of the patients for whom that intervention is initiated. Our follow-up findings reinforce the policy recommendations made by stakeholders, i.e. the introduction and reimbursement of a mental health consultation in family practice and integration of primary care psychologists. Quality improvement interventions may be a strategy to overcome premature discontinuation of non-pharmacological support by GPs.