The aim of this research was to examine the relations between personality traits, attachment in romantic relationships and mental health. 242 participants over the age of 18 took part in the research. The research was conducted online and the instruments used were: Sociodemographic Data Questionnaire, Big Five Inventory, The Maladaptive Covert Narcissism Scale – MCNS, Modified Brennan Inventory of Experiences in Close Relationships and Depression, Anxiety and Stress Scale (DASS-21). The results showed that there is a statistically significant positive relation between neuroticism, vulnerable narcissism and avoidant and anxious attachment in romantic relationships with mental health problems. Furthermore, the results of the hierarchical regression analysis showed that neuroticism and vulnerable narcissism are statistically significant positive predictors of mental health problems, while attachment predicts mental health problems, although its dimensions are not individually significant. Finally, the mediating effect of attachment in romantic relations was tested in the relation between personality traits and mental health. The results showed that anxious attachment mediates the relation between neuroticism and mental health problems, as well as the relations between vulnerable narcissism and mental health problems. Also, the mediation effect of avoidant attachment on the relation between neuroticism and mental health problems was found. However, the mediation effect of avoidant attachment on the relation between vulnerable narcissism and mental health problems was not found.