Most heart transplant candidates are equipped with left ventricular assist devices (LVADs). LVAD therapy is associated with characteristic psychiatric and psychosocial problems. To investigate the mental states of heart transplant candidates, psychiatric diagnosis, psychological or behavioral problems, and the need for treatment were evaluated around the time of registration to the waiting list and during follow-up. Saitama Medical University Hospital has been designated a hospital for heart transplantation since October 2002. The subjects were 14 heart transplant candidates (9 male candidates and 5 female candidates, mean age 29 years) at the hospital from September 1997 to October 2005. These 14 candidates were equipped with LVADs. The waiting periods on LVAD support were from 119 days to 1028 days, and the average waiting period was 313 days. Six candidates among the 14 had more than one DSM-IV diagnosis. Seven candidates were diagnosed with adjustment disorder, which was the most frequent diagnosis. Three candidates had depressive disorder, one had psychotic disorder, and one had dissociative disorder. Three candidates had acute cognitive dysfunction (delirium) due to their general medical condition. All three had other disorders with mainly psychological elements. Nine candidates (64%) were diagnosed with disorders with mainly psychological elements. Antipsychotics were used for the candidates in psychotic states and with delirium, and there was a need for crisis intervention. Antidepressants and antianxiety drugs were used for the candidates with depressive disorder; they needed intensive observation. Four candidates (28%) needed some attention and some antianxiety drugs or hypnotics. Psychiatric interventions were not necessary in five candidates (36%).