Atrial fibrillation (AF) is a common arrhythmia, and many cases may be undiagnosed. It is unsettled whether screening for AF and subsequent treatment if AF is detected, can improve long-term outcome. The primary objective of the NORwegian atrial fibrillation self-SCREENing trial (NORSCREEN) is to assess whether self-screening for AF with continuous ECG for 3-7 days in individuals aged 65 years or older with at least one additional risk factor for stroke, and initiation of guideline-recommended therapy in patients with detected AF, will reduce the occurrence of stroke. The study is a nationwide randomized, open, siteless, controlled trial. Individuals ≥65 years of age are randomly identified from the National Population Register of Norway and are invited to a digital inclusion/exclusion test. Individuals passing the inclusion/exclusion test are randomized to either the intervention group or the control group. A total of 35,000 participants will be enrolled. In the intervention group, self-screening is performed continuously over 3-7 days at home with a patch ECG device (ECG247) at inclusion and after 12-18 months. If AF is detected, guideline-recommended therapy will be initiated. Patients will be followed for five years through national health registries. The primary outcome is time to stroke. The first participant was enrolled in the NORSCREEN trial on September 1, 2023. The results from the NORSCREEN trial will provide new insight regarding the efficacy of digital siteless self-screening for AF with respect to stroke prevention in individuals at increased risk of stroke.