Aims The purpose of this study is to evaluate the accuracy and validity of the determination of cause of death (COD) and manner of death (MOD) at the completion of the forensic autopsy prosection. Methods We analysed 952 autopsy cases conducted from 2019 to 2020 and compared every patient’s COD, other significant contributing factors to death (OSC), and MOD after prosection to their COD, OSC and MOD after completion of the final autopsy report. Results We found that 83% of cases (790 patients) did not have an unexpected change and 17% of cases (162 patients) exhibited a true change in their final diagnosis; the relationship between age and changes in COD and MOD was significant. Conclusions Our findings indicate that in the majority of forensic autopsy cases, medical professionals can reasonably complete death certification after the autopsy prosection. In addition to improving the accuracy of COD and MOD, advances in this field will enhance timely decedent affairs management, timely investigations of crimes and timely closure to families who have lost loved ones. We recommend implementing combined interventional education and consultation with expert pathologists, and a well-followed structured method of death classification as the best course of practice. Data are available on reasonable request.