Low socio-economic status is recognized as one of the risk factors for SIDS. In this study we have pointed out the similarities between families that have SIDS cases and families in which infant non-accidental injury has been proven, as well as the differences between them and the general population. This study was conducted in Montenegro, comparing 30 cases of SIDS with 25 cases of known infanticides and with a control group (60 cases) consisting of live newborns and their mothers from the general population, randomly selected from hospital-born newborns without exclusion criteria. We combined and compared the infant characteristics and mother characteristics between the above cases. There were significant similarities between the SIDS group and the infanticide group in terms of the following characteristics: the education level of the mothers (p = 0.086); maternal employment (p = 0.278); and place of residence (p = 0.269); while there were differences between the two groups regarding hospital birth (p = 0.027) and marital status (p = 0.011). The SIDS and infanticide groups, combined, had higher incidences of: out-of-hospital deliveries (p < 0.001); uneducated mothers (p < 0.001); unemployed mothers (p < 0.001); low socio-economic status (p < 0.001); and cases outside of marriage (p < 0.001), compared to the control groups. This study indicated a possible higher incidence of non-natural death among SIDS cases, as reflected by low socio-economic status and linked attributes, which is explained by their similarities with the infanticide groups and differences with the control groups.