Current literature on narcissistic personality disorder has emphasized a distinction between grandiose and vulnerable narcissism. Some researchers have further suggested that narcissistic persons fluctuate between grandiose and vulnerable narcissism. However, this perception has been confined largely to clinical experience with no systematic research testing the hypothesis. Clinicians and clinical psychology professors in the current study identified 143 persons who fit a description of either a grandiose or a vulnerable narcissist and indicated the extent to which these persons ever demonstrated traits of the complementary variant. The results supported the fluctuation hypothesis, particularly for episodes of vulnerable narcissism in persons identified as a grandiose narcissist. Correlations of the grandiose and vulnerable narcissism traits with a brief five-factor model measure corroborated past trait descriptions of the 2 respective variants of narcissism. The results of the current study are compared with existing cross-sectional and longitudinal research, and suggestions for future research are provided. (PsycINFO Database Record