An electronic health record (EHR) will be established nationwide in Switzerland in 2020. Patients can decide on their own whether they open an EHR. It is still unclear what might influence the patient decision. For this reason, we performed an online survey among the Swiss population to study whether there is a lack of knowledge on the EHR which impacts the willingness to open a personal health record and agree to health data sharing. A questionnaire with 13 question was distributed in a period of 4 weeks. More than 1200 participants replied to the survey. The results were analyzed with statistical methods. There are correlations between some of the questions in our survey. We conclude that the willingness to open a personal health record directly depends on the trust into the enabling technology.