We report a patient who developed spontaneous confabulation following surgical clipping of an anterior communicating artery aneurysm. An autobiographical memory test was used to measure the emotional valence of the patient's self-representations in true and false memories. We found that his confabulations included significantly more positive self-representations than his true memories and that the overall valence of his confabulations was more positive than that of his true memories and than that of the memories of five healthy control participants of the same age and educational attainment. It is proposed that while cognitive dysfunction may explain how confabulations are formed, emotional factors may explain which specific confabulations are constructed.