Background: High-risk intravenous injection errors are fatal to patients and bring great harm. Thus, it is of vital importance to identify the causes of such errors and establish a preventive system and safety culture among the health care professionals to prevent systematic injection errors in the hospital. Objective:The purpose of the present study was to identify the causes of and problems associated with high-risk intravenous injection errors from the perspective ofhealthcare providers. Methods and Material:A focus-group interview was carried out with 13 health care professionals (7 nurses, 3 doctors, 3 pharmacists) who work at a university hospital in Daejeon City and have work experience in and knowledge of high-risk intravenous injection. Results: Three causal categories responsible for errors emerged: human-related, injection procedure-related, and environmental factors. Specifically, lack of knowledge and awareness of high-risk medications, carelessness in controlling the speed and drip of fluids, injecting the wrong fluid, unclear verbal prescriptions from doctors, inappropriate medication management, a shortage of medicators, and a lack of injection experience were identified as the most common problems responsible for nurses’ errors when administering high-risk intravenous injections. Conclusion: Our results may serve as baseline data for establishing a safety culture around high-risk intravenous injection administration.