Introduction: the neurobiology of suicide in bipolar disorder (BD) is still unknown. A recent meta-analysis showed reduced callosal areas in bipolar patients in comparison to healthy volunteers, but these studies did not differentiated type or phase of the disease, as well, did not evaluated history of suicide attempt. Objective: this study aimed to examine anatomical integrity of corpus callosum in suicidal and non-suicidal euthymic bipolar I patients compared to healthy controls using magnetic resonance imaging (MRI). Methods: twenty-nine euthymic bipolar I patients, 15 with suicidal history and 14 without history of suicide attempt, and 9 healthy controls underwent clinical assessment by SCID-I and MRI scan. The exclusion criteria were history of neurological illness, head trauma or history of substance abuse in any time. The corpus callosum (CC) was outlined at the midsagittal slice and semi-automatically segmented into seven sections using Witelson´s protocol. Results: there were no group differences in total brain (F=0.34;p<0.96), white matter (F=0.91;p<0.40) and gray matter volumes (F=0.29;p<0.75). There was a significant reduction in CC subregion 06 in bipolar patients with (F=4.26;p<0.05) and without suicide attempts (F=7.07;p<0.01) in comparison to controls. No differences for any CC subregions were observed between bipolar patients with and without suicide attempts (all p’s >0.05). Conclusion: although no significant differences for any CC subregions were observed between suicidal and non-suicidal bipolar I patients, the posterior callosal reductions observed in this BD patients are in agreement with literature, suggesting a failure to integrate information across the hemispheres may contribute to pathophysiology of BD.