Empirical studies on adult attachment show differential associations between secure and insecure attachment styles with some of the sexual behaviours. However, studies on the relationship between attachment styles and the internal working models (IWMs) of attachment relationships with sexual compulsivity, are scarce. With the purpose of analysing the relationship between attachment styles and sexual compulsivity with several aspects of sexual behaviour, a sample of 187 sexually active adults, 81 males and 106 females, aged between 18 and 64 (M=32,82; SD = 10.07) was studied. Results on gender differences have shown, as expected, that males reported an earlier age for the first intercourse, more sexual partners, and higher sexual compulsivity. The study of the associations between attachment styles and IWMs of attachment with sexual compulsivity and other sexual behaviours has shown that participants with a dismissing attachment style reported seeking more short-term relations and having more sexual partners, whereas participants with more preoccupied and fearful attachment styles reported higher sexual compulsivity. Correlation analyses with the IWMs of the self and the others have shown that the IWM of the others was independent of the assessed variables, but participants with a more negative IWM of the self reported having more sexual partners. Regression analyses, with sexual compulsivity as the dependent variable, have shown a model with two independent variables, short-term relationships seeking and preoccupied attachment style, which explained 18% of total variance. Results were discussed according to literature and their implications for the assessment and modification of sexual compulsivity in adulthood.