Ethylene glycol (EG) is used in antifreeze and other industrial products. It metabolizes to glycolic acid (GA) and oxalic acid (OX) that cause metabolic acidosis and are mainly responsible for the toxicity of EG. During 2010-2014, EG or GA was found in 25 postmortem cases in Finland. Of these cases, 21 were classified as fatal EG poisonings and 3 were classified as methanol (MeOH) poisonings. In this study, we report the concentrations of EG and GA in postmortem blood and urine samples of fatal EG or mixed MeOH/EG poisonings. In the fatal EG poisonings, the median EG and GA concentrations were 0.87 and 1.6 g/L in blood and 4.3 and 5.3 g/L in urine. The median urine-blood ratios were 3.8 and 3.1 for EG and GA. These results warrant the use of urine as a primary matrix for screening. In EG positive cases, the quantification of both EG and GA in blood is crucial as GA concentration appears to best indicate a fatal poisoning with an approximate threshold of 1.5 g/L. The measurement of urinary OX does not offer much additional value to toxic alcohol screening as it may originate from varying dietary conditions.