Assurance case development (ACD) is a novel approach for demonstrating that a system is safe for use. Assurance cases comprise various project information, including requirements and their traceability to other artifacts. A practitioners’ survey was performed to understand how requirements engineering and ACD activities currently interplay. This study aimed to identify the state of practice of ACD, the existing integration between requirements engineering and ACD, and the practitioners’ opinion on this integration. The results revealed that the interplay occurs across all requirement engineering activities and that practitioners perceive benefits such as raising safety assurance awareness, early traceability development, and early identification of assurance evidence needs. Practitioners see requirements specification and change request analysis as the most suitable activities for integrating ACD and requirements engineering.