Introduction: Patient transitions between primary and hospital care include referral, discharge, and simultaneous care by the outpatient clinic and the general practitioner (GP). Research on referrals and discharge shows that safety incidents in these transitions are common. We developed the multifaceted Transitional Incident Prevention Programme (TIPP), which aims to improve transitional patient safety preventing future incidents. With this study, we aim to evaluate the effectiveness of the TIPP programme on transitional patient safety, and to evaluate its implementation and the acceptance in GP-practices and hospitals. Methods: The TIPP intervention study is a controlled before and after study combined with qualitative methods. The study will be conducted in both rural and urban settings including three hospitals, together with referring primary care practices. The TIPP intervention is aimed at three aspects of transitional safety: 1) Healthcare process, 2) Transitional patient safety culture, and 3) Patient participation. Together with the participating hospital departments, GPs and patients, we will develop a tailored improvement programme, taking into account the different context of each setting.