Previous research suggests that insecurely attached individuals may, in some cases, have a higher risk of developing negative health symptoms than securely attached ones. We conducted two studies (Study 1, n = 191; Study 2, n = 216) aimed at broadening this finding. We analysed the relationships between two distinct dimensions of insecure attachment (anxious and avoidant) and several classes of negative physical and mental health symptoms. Additionally, we placed emotion regulation difficulties in the role of potential mediator of these relationships. Our results indicated that both anxious and avoidant attachment were positively related to health symptoms on the level of bivariate correlations. However, when both of them were controlled within one mediation model, it was only attachment anxiety, and not attachment avoidance, that proved to be a significant, positive predictor of most health symptom classes: vegetative, agoraphobic, social phobia symptoms and global symptom severity index (which reflects a broad range of negative health symptoms). These relationships were indeed mediated by emotion regulation difficulties. Our results support the notion that (1) different dimensions of insecure attachment can have differential consequences for physical and mental health, and (2) emotion regulation can be one of the mechanisms that explain the links between attachment and health.