Preoperative and postoperative psychiatric evaluation were done for 51 patients who were undergoing open-heart surgery. The incidence of postoperative psychopathological complications following open-heart surgery was 27.5%. This rate is comparable to that of previous studies. Neurotic reactions occurred in eight patients, delirium in five, and acute psychotic reaction in one. Of those variables which were previously suggested to influence the high incidence, the demographic factors and the severity of preoperative illness were correlated with postoperative psychopathologic dysfunctions. No somatic variable associated with intraoperative or postoperative procedures has been proven to correlate. By preoperative psychiatric evaluations, the patients could be divided into three groups: the Anxiety group, the Denial group, and the Adjusted group. The most important psychological finding was that in patients who demonstrated a high degree of preoperative anxiety or who could not express preoperative anxiety, postoperative psychological complications developed more frequently. With these findings, the preoperative psychiatric interview was recommended for prevention and reduction of postoperative psychiatric complications.