Objective: As obsessive-compulsive disorder (OCD) is a relatively common psychiatric disorder with a significant suicide risk, the individuation of potential biomarkers of suicidality, such as cholesterol levels, may enable recognition of at-risk subjects. Therefore, the aims of this study were to: 1) evaluate potential differences in clinical and laboratory parameters between patients with and without alexithymia and compare them with healthy controls; and 2) investigate which clinical and laboratory variables were associated with suicidal ideation. Methods: 79 drug-naïve adult outpatients with a DSM-IV diagnosis of OCD were recruited. Alexithymia was measured with the 20-item Toronto Alexithymia Scale (TAS-20), suicidal ideation was assessed with the Scale for Suicide Ideation, and depressive symptoms were evaluated with the Montgomery-Åsberg Depression Rating Scale (MADRS). Serum lipid levels of 40 healthy controls were also evaluated. Results: Alexithymic patients had altered serum lipid levels in comparison with non-alexithymics and healthy controls. Using a linear regression model, the presence of symmetry/ordering obsessions and compulsions, lower HDL-C levels, and difficulty in identifying feelings dimension of the TAS-20 were associated with higher suicidal ideation. Conclusions: Alexithymic individuals with OCD may exhibit dysregulation of the cholesterol balance, which in turn may be linked to suicidal ideation. Further prospective studies are required to elucidate this potential association.