The perception of the 20 adverse events of targeted therapy for metastatic renal cell carcinoma was compared among medical professionals. Thirty-seven oncologists, 167 nurses and 79 pharmacists participated in the survey, and the response rate was 61.9%, 98.2%, 84.9%, respectively. Results showed that the most serious adverse event was GI perforation (8.83 points, 10 being the most serious), whereas the least serious was anemia (5.32 points). There were significant differences among oncologists, nurses and pharmacists especially for the moderately-serious adverse event such as wound-healing complication and lymphopenia. Adverse Events Composite Score (AECS) for each targeted therapy was calculated by multiplying adverse event incidence rate and seriousness score. Sunitinib had the highest score at 6.86 point and bevacizumab had the lowest at 2.1. Among professional groups oncologists showed the lowest AECS, whereas nurses had the highest. The gap on the perception of the adverse events among medical professionals needs to be reduced to get better outcomes of medical therapies for cancer patients.