Abstract Background Previous multidomain lifestyle intervention trials to prevent cognitive decline in non‐demented elderly have found conflicting effects, with positive findings including the multidomain FINnish GERiatric intervention (FINGER) study (Ngandu T, Lehtisalo J, Solomon A, et al. Lancet 2015), and in specific at‐risk subgroups in other trials (Moll van Charante EP, Richard E, Eurelings LS, et al. Lancet 2016; Andrieu S, Guyonnet S, Coley N, et al. Lancet Neurol. 2017). As part of a world‐wide effort to replicate and build on these results, FINGER‐NL aims to investigate the effectivity of a 2‐year multidomain lifestyle intervention in Dutch older adults to prevent cognitive decline. Method FINGER‐NL is a Dutch multi‐center, randomized, controlled, multidomain lifestyle intervention trial among 1,206 adults at risk for cognitive decline with a duration of 24 months. Inclusion criteria are 60‐80 years of age and presence of both modifiable (based on LIfestyle for BRAin health (LIBRA) score) and non‐modifiable (family history, worries about subjective cognitive decline) dementia risk factors. Participants will be randomized in a 1:1 ratio to the structured intervention group or the self‐guided control group. The multidomain lifestyle intervention comprises 8 modules, namely physical exercise, cognitive training, management of metabolic and vascular risk factors, nutritional counseling, Souvenaid®, sleep counseling, stress management, and social activities. The structured intervention group receives a personalized, supervised and hybrid (both online and at study site) intervention consisting of group meetings and individual sessions. The self‐guided control group receives online lifestyle‐related health education. Primary outcome is 2‐year change from baseline on a cognitive composite score covering processing speed, executive function and memory. Secondary outcomes including changes in specific cognitive domains, Amsterdam Instrumental Activity of Daily Living Questionnaire (A‐IADL‐Q), LIBRA score, ...