Background: The aims of this study were to examine the relationships between Cloninger's psychobiological model of personality, defense styles, and severity of grief, and to identify the influential temperament and character dimensions that differentiate subjects with prolonged grief from those without prolonged grief. Method: A sample of 72 bereaved elderly persons for whom the loss of a loved one occurred on average 2.58 years (SD = 1.92) prior to participation in this study were assessed using the Inventory of Complicated Grief-Revised, the Temperament and Character Inventory, and the Defense Styles Questionnaire. Using the algorithm developed by Prigerson et al. (2009) for diagnosing prolonged grief, 18 of our participants were identified as having this disorder. Results: A multiple regression analysis revealed that time since loss, persistence, an immature defense style, and the age of the bereaved person positively predicted severity of grief, whereas cooperativeness and the age of the deceased loved one negatively predicted severity of grief. A binary logistic regression showed that gender, a close kinship relation to the deceased, time since loss, self-directedness (SD), and self-transcendence (ST) were predictors of prolonged grief, whereas the age of the deceased and cooperativeness (CO) were negatively related to prolonged grief. Limitations: Our sample was small. Self-report measures of grief were not supplemented with clinical evaluation. Conclusion: Our results suggest that only character dimensions (high SD and ST, and low CO) are involved in the psychopathology of prolonged grief. Also, according to Cloninger's character cube (Cloninger, 2004), high SD and ST scores, and low CO scores are indicative of a fanatical character. (C) 2010 Elsevier B.V. All rights reserved.