SEVERIN, K, P. DZAJA, M. SPERANDA, M. DIDARA, D. KONJEVIC, E. SATROVIC, K STARCEVIC: Estimation of red deer (Cervus elaphus) post mortal interval based on the biochemical parameters of vitreous fluid using linear regression analyses. Vet. arhiv 88, 511-519, 2018. Vitreous fluid is a stable biological fluid, which is well-protected from contamination and post mortem degradation, which makes it suitable in forensic pathology for determination of the post mortem interval (PMI). The present study was conducted to discover the correlation between increasing PMI and levels of various vitreous biochemical parameters (sodium, calcium, magnesium, chloride, potassium, phosphor, AST, urea, creatinine, total protein, glucose, total cholesterol). The estimation of PMI in red deer is of great interest in cases of illegal hunting. The vitreous humour samples were collected from six red deer carcasses. The eyes were enucleated, covered by parafilm and aluminium foil, packed in a small container and maintained at +4 degreesC. Sampling of vitreous fluid was done again at 8, 10 and then regularly each 10 hours until finally 90 hours after death. A significant linear correlation was found for potassium, sodium and chloride (P<0.0001). The present study revealed that biochemical analysis of vitreous fluid could be used to determine post mortem interval in red deer. Key words: vitreous fluid; potassium; sodium; chloride; red deer