For several years, there has been a growing interest for the two phenotypes of pathological narcissism. Narcissistic grandiosity is characterized by arrogance, vanity and a dominant attitude, while narcissistic vulnerability is characterized by the unconscious experience of helplessness, emptiness, low selfesteem and shame. The psychodynamic mask model of narcissism proposes that narcissistic individuals have a high self-esteem on the surface that hides low self-esteem deep down inside. Thus, researchers have been interested in the two facets of self-esteem in order to gain a better understanding of pathological narcissism. While explicit self-esteem is considered to be the result of conscious, deliberate and thoughtful processes, implicit self-esteem is seen as unconscious, automatic and affective reactions. Since, few clinical studies have investigated the link between pathological narcissism and the two facets of self-esteem. Eating disorders (ED) appear to be a very relevant population considering that it has been extensively demonstrated that self-esteem is an important risk factor and, several studies have also shown the presence of pathological narcissism in women with ED. The present thesis aims to deepen current knowledge of the links between pathological narcissism and self-esteem in ED. Participants with ED (n = 69) have been compared to participants with an anxiety disorder (n = 51) and participants without history of psychiatric disorder (n = 93) on measures of explicit self-esteem, implicit self-esteem and pathological narcissism. Explicit self-esteem and pathological narcissism have been assessed using self-reported measures, while implicit self-esteem has been measured using the implicit association task (i.e. IAT). The first specific objective of the thesis is to examine the two phenotypes of pathological narcissism in relation to explicit and implicit selfesteem in a clinical sample with ED, a psychiatric control group and a healthy control group. The results indicate that participants with an ED showed lower self-esteem and higher levels of narcissistic grandiosity compared to participants without a history of psychiatric disorders. The results also highlight the importance of narcissistic vulnerability in women with ED since their levels were significantly higher of the psychiatric control group and the healthy control group, suggesting a specific contribution of narcissistic vulnerability regarding eating pathology. Rather than demonstrating a divergence of the two facets of self-esteem, our results suggested low explicit and implicit self-esteem (convergence). Again, our results indicate that low explicit self-esteem better explained narcissistic vulnerability than divergence between both facets of self-esteem. Although these results do not validate psychodynamic mask model of narcissism, they nevertheless highlight the important contribution of narcissistic vulnerability and explicit self-esteem in ED. The second specific objective of the thesis was to examine the specific dimensions of pathological narcissism in explaining dysfunctional eating attitudes and behaviors in women with anorexia nervosa (n = 27) and bulimia nervosa (n = 23) while controlling for explicit self-esteem. Our results suggest that anorexia nervosa and bulimia differ significantly in regards to their associations between the facets of pathological narcissism and dysfunctional eating attitudes and behaviors. These findings also shed light on the independent contribution of a narcissistic vulnerability dimension, hiding the self, in explaining eating concerns and objective binge eating in women with anorexia nervosa. This has shown that hiding the self contributes over and above a longstanding risk factor, low explicit self-esteem. Thus, the present thesis reinforces the idea that the narcissistic vulnerability must be more widely recognized and that, efforts must continue to better understand its impact on treatment.