Objective: Our aim was to evaluate the relationship between adherence to different Dietary Approaches to Stop Hypertension (DASH) diet indices and the risk of depression. Design: In a prospective study we assessed 14051 participants of a dynamic (permanently ongoing recruitment) prospective cohort (the Seguimiento Universidad de Navarra (SUN) Project), initially free of depression. At baseline, a validated FFQ was used to assess adherence to four previously proposed DASH indices (Dixon, Mellen, Fung and Günther). To define the outcome we applied two definitions of depression: a less conservative definition including only self-reported physician-diagnosed depression (410 incident cases) and a more conservative definition that required both clinical diagnosis of depression and use of antidepressants (113 incident cases). Cox regression and restricted cubic splines analyses were performed. Results: After a median follow-up period of 8 years, the multiple-adjusted model showed an inverse association with the Fung DASH score (hazard ratio (HR)=0·76; 95 % CI 0·61, 0·94) when we used the less conservative definition of depression, and also under the more conservative definition (HR=0·63; 95 % CI 0·41, 0·95). We observed a weak inverse association with the Mellen DASH score, but no statistically significant association was found for the other definitions. The restricted cubic splines analyses suggested that these associations were non-linear (U-shaped). Conclusions: Moderate adherence to the DASH diet as operationalized by Fung and Mellen was related to lower depression risk. Since these associations were non-linear, additional prospective studies are required before the results can be generalized and clinical recommendations can be given.