Background Compassion is considered the cornerstone of nursing practices and professionalism. However, a decrease in compassion may increase medical errors and adversely affect patient safety. Aims The study was conducted to determine clinical nurses' compassion levels and their tendency to make medical errors, and to find whether their compassion levels affect their tendency to make medical errors. Methods A cross-sectional, descriptive and correlational design was used. The study was conducted with 309 nurses working at a university hospital. The study data were collected by using the Compassion Scale and Medical Error Tendency Scale in Nursing. Results The nurses' compassion levels were moderate, and their medical error tendency levels were low. The comparison of the mean scores obtained from the Compassion Scale and Medical Error Tendency Scale in Nursing revealed a weak positive significant relationship (p < .001). No statistically significant difference was determined between the mean scores obtained from the Compassion Scale by the participants who made medical errors at least once during their professional life and the mean scores obtained by the participants who did not (p > .05). It was found that the mean score for the mindfulness subscale of the Compassion Scale and the length of service were determined to be the factors that significantly affected the participants' tendency to make medical errors (R = 0.42, R-2 = 0.181, F = 3.771, p = .000). Conclusion The nurses' tendency to make medical errors decreased as their compassion levels increased, and that compassion was an important predictor of tendency to make medical errors.