Clinician- and self-rating of suicidal ideation (SI) are often discrepant. The aim of this study was to determine: 1) Association between discrepant self- and clinician-rated SI with clinical characteristics, depression remission and SA (SA) risk; 2) which SI assessment (self or clinician) predicted depression remission and risk of SA. LUEUR and GENESE are two large, prospective, naturalistic cohorts of French adult outpatients with unipolar depression treated and followed for 6 weeks. SI presence was assessed and defined with a score to the suicidal item of the Montgomery-Åsberg Depression Rating Scale ≥3. Discordant SI was defined as SI detection by only one of the two evaluators (patient or clinician). In both cohorts, 49.3 % (GENESE) and 34 % (LUEUR) patients had discordant SI. Clinical characteristics were more severe, and risk of SA was higher in patients with current SI (concordant and discordant) than in patients without SI and in the concordant than in the discordant group. Prediction of the risk of SA and of depression non-remission was comparable by the two ratings. Patients with SI (concordant and discordant) have more severe clinical characteristics and patients with concordant SI are the most at risk of SA during the follow-up. It is crucial to assess SI and to improve how it is evaluated.