To investigate the role of familial factors for suicidal ideation, 48 psychiatric patients belonging to 20 nuclear and three-generation families were personally interviewed. The effect of familiality on suicidal ideation was estimated through the use of mixed model analysis with family as random effect and gender, age and depressive score as fixed effects (covariates). The effect of family was found to be statistically significant (p=0.024) for the whole group of patients and for the subgroup of males (p=0.048), but not female patients; significance persisted for the whole group (p=0.030) and was reduced to indicative level for males (p=0.069), when psychiatric diagnosis was also considered as an additional potentially confounding factor. These results show that the occurrence of suicidal ideation has a familial component, stronger among males than females. This may be an additional explanation (besides those related to various other biological and sociocultural factors) for gender differences in suicidal behavior.