Vitreous humour (VH) is a quite stable and well-protected biological fluid from post-mortem degradation and contamination, making it a usable specimen in forensic pathology. We aimed to analyse the biochemical markers in VH stored for one month at -20 degrees C and to compare them with those of serum samples of the same deceased people. To the best of our knowledge this is the first time this has been reported in the literature. Serum levels of sodium, potassium and calcium, phosphorous and VH levels of calcium, creatinine, and urea were not statistically different between fresh and stored samples. There was no significant difference in VH urea and creatinine levels whereas serum levels were significantly decreased by the 15th and 30th days. In conclusion, urea and creatinine levels in VH showed adequate stability after one month of storage at -20 degrees C, whereas large variations were seen in the stability of inorganic components such as Na, K, Mg, Cl, and P. Our results indicate the validity of using post-mortem VH samples for urea and creatinine but not for VH stored at -20 degrees C for a limited time frame. The differences in sample handling before being stored at -20 degrees C may introduce bias on some components of VH.