Using post-mortem vitreous humour (VH) electrolyte in estimating the post-mortem interval (PMI) is not well studied in the infant population. We hypothesize that VH can be useful in estimating PMI in shorter PMI. This 5-year retrospective study investigated the changes in VH electrolytes (Na+, Cl- and K+) with respect to shorter PMI. This study examined PMI <48 hours and stratified the PMI into two groups (i.e. <24 hours and 24-48 hours). The electrolyte levels were compared and linear regression analysis was performed between the two groups. Our result showed that K+ increases with PMI and is a relatively good estimator (compared to adults) for PMI especially when PMI was <24 hours. Na+ and Cl- showed some evidence that they decrease with PMI but have no use in estimating PMI. The results from this study suggested K+ is useful in estimating PMI but limited to only when the PMI is <24 hours.