Estimation of the minimum post mortem interval (PMI) is the essential role of forensic entomology. The accurate determination of this interval depends on the correct larval identification and accurate estimation of larval age. One method of larval age estimation is the larval length measurement. Killing methods and the type of preservative solutions can greatly affect the larval length and therefore reduce the accuracy of PMI estimation. This study was conducted to determine which killing method and preservative can preserve the best larval length of Chrysomya marginalis. Third instar C. marginalis larvae were either placed live in the preservatives, 10% formalin, 70% ethanol, XAA, Kahleˊs solution and Pampleˊs fluid, or killed by boiling water (BWK) before being placed in the same preservatives. The larval length was recorded after day 1, 3, 5, 7 and 15 and for BWK larvae only; the length was recorded immediately after killing the larvae and before being placed in the preservatives. The larval length of C. marginalis was significantly affected by killing method (live or BWK) and the type of the preservative used. The mean length of the larvae placed live in the preservatives
decreases significantly than those killed by boiling water before being placed in the preservatives.It was observed that killing larvae by boiling water then preserved in 10% formalin and Kahleˊs solution is the best method for preserving the larval length, but 10% formalin is not recommended if DNA recovery is desired.