Background: The relationship between insight and suicidal behavior among psychotic patients is poorly studied and possibly mediated by clinical variables. Objectives: Our goal was to investigate clinical differences in suicidal and non-suicidal delusional disorder (DD) patients, and to evaluate the relationship between insight, psychotic and depressive symptoms. Methods: Cross-sectional study in 64 consecutive DD patients. For assessment, we used the Positive and Negative Syndrome Scale (PANSS), the Hamilton Rating Scale for Depression (HRSD-17), the Columbia Suicide Severity Rating Scale (C-SSRS), the Personal and Social Performance Scale (PSP), and the first three items of the SUMD scale for insight. The sample was divided according to the presence of suicide attempts. To investigate psychopathological associations, bivariate correlation coefficients were used. Age at onset served as covariate in subsequent analyses. Results: Suicidal DD patients had higher depressive symptoms and were more frequently admitted than non-suicidal patients. A logistic regression model confirmed that insight, depressive symptoms and age at onset were predictors of suicidal behavior. Unawareness of the effects of medication was negatively related to depressive symptoms. After adjustment, depressive symptoms were weakly correlated to better insight into the effects of medication. No other statistically significant correlations were found. Discussion: Depressive symptoms, insight and age at onset of disease may be potential predictors of suicidal behavior in DD patients.