Ethanol analysis is the most frequently performed assay in forensic toxicology laboratories. Interpretation of postmortem ethanol findings are often confounded by postmortem production of ethanol. Many species of bacteria, yeast, and molds are capable of producing ethanol from a variety of substrates. The probability of postmortem ethanol synthesis increases as storage temperature and the interval between death and autopsy increases. It is often difficult to distinguish between postmortem ethanol production and antemortem alcohol ingestion. This review presents a discussion of the criteria for the identification of postmortem ethanol synthesis and factors to consider in the interpretation of postmortem ethanol findings. The criteria include case history, condition of the specimens, types of microbes present, atypical fluid and tissue distribution of ethanol, the concentration of ethanol present, and the detection of other alcohols and volatiles. With careful consideration of all the information available, a valid interpretation of the source of ethanol, whether it be from antemortem ingestion or postmortem production, can be made.