BACKGROUND: The Medical Informatics Initiative (MII) introduced a broad consent form (MII-BC) encompassing clinical, insurance, and biomaterial data, along with re-contacting options. In the emergency department (ED), outpatient and inpatient patients of all illnesses and severity could be reached early in their treatment course. The BC-ED (Broad Consent in the Emergency Department) project uniquely investigated the implementation of MII-BC in EDs, exploring feasibility, selection bias and patients' perceptions of voluntariness, information recall, motivation, and satisfaction. METHODS: The BC-ED project involving four university hospital EDs in Germany, is part of CODEX+ (Collaborative Data Exchange and Usage), an initiative within the Network University Medicine (NUM). To minimize selection bias, a systematic sampling approach (every 5th/30th patient) was applied, with patient recruitment and consent processes adapted to local conditions and therefore varying among sites. Data collection included patient questionnaires, surveys completed by study nurses, and routine clinical data. Analysis was conducted descriptively using SPSS. RESULTS: Of 1,138 patients approached, 553 (48.6%) were capable of giving consent. Of 353 patients who could not consent, primary reasons included language barriers (35.4%) and inability to grasp study details (21.5%). Of all eligible patients, 3.3% could not be contacted. Of 535 (47.0%) patients able to consent and contacted, 313 consented to the MII-BC. Resulting in a consent rate of 27.5% corresponding to the baseline population and 58.5% of those contacted. Motivations for consenting were general support for research (85.3%) and the desire to help future patients (78.2%). Patients generally reported a high level of understanding and satisfaction with the consent process, reporting comprehensive understanding of scientific data use (89.8%) and associated risks (82.2%). However, discrepancies were noted between consented options and patient recall. CONCLUSIONS: This study is the first to investigate the implementation of the MII-BC in the challenging ED environment. With a consent rate of 27.5% total baseline population and 58.5% of those contacted, it demonstrates that patients were able and willing to participate in research. Reasons for non-consent were barriers like language and medical conditions. Strategies to address these barriers are crucial for inclusivity. Although patients generally understood the consent process, discrepancies in recall highlight the need for improved comprehension strategies. TRIAL REGISTRATION: German Clinical Trials Register on 25 October 2022 (DRKS0003054).