Suicide is a major public health concern in old-age people. Previous studies have shown a particular sensitivity to unfairness in suicide attempters. Here, we investigated the neural mechanisms underlying responses to unfairness in this population. A sample of 57 male and female participants aged 65 and more was recruited, comprising 19 depressed patients with a history of suicide attempts, 19 depressed patients without such history, and 19 healthy controls. Participants were subjected to the Ultimatum Game task while undergoing functional MRI in a 3T scanner. In this task, participants have to make decisions in conditions of various levels of unfairness from fair to very unfair. Our results showed no significant differences in behavioral responses across the groups (acceptance rates, reaction times). However, a group x level of unfairness interaction was found in two brain regions: the left anterior cingulate cortex (BA32) and the right middle prefrontal gyrus (BA9/46). Post-hoc analyses revealed differences between both patient groups and healthy subjects without any difference between patient groups: Variations in activations in these two regions across the four levels of unfairness were similar between the two patient groups but differed from healthy controls. Our findings suggest that old-age patients with depression, regardless of a history of suicide attempts, exhibit distinct neural processing of social adversities when compared to healthy controls. Lack of difference between attenpters and non-attempters may be due to the small sample size. An alternative explanation is that alterations in the processing of unfairness during depression may contribute to the early steps of suicidal process.