Lost circulation refers to loss of part of or whole drilling fluid into the formation while drilling operataion. It wastes costly mud and wastes time spent on rig operations. In this study, the investigation of a natural plant called, Prosopis Farcta (PF), has been done to show its effectiveness as a natural lost control material. A series of experimental tests have been conducted in order to discover the effectiveness of the PF as an LCM. Moreover, different particle sizes of the PF have been tested to find out the optimum size. Furthermore, a variety of PF concentrations have been tested in order to investigate the effect of the LCM percentage. And finally, for the purpose of comparison, a similar particle sizes and LCM precents of the most used conventional LCM, calcium carbonate have been tested as well. The results show that the filtrate rate of the reference mud (without additives) was 32 milliliters in 30 minutes. The most achieved reduction in the fluid losses with the addition of CaCO3 LCM was about 47% and this was by adding 20 ppb of the fine sized CaCO3 into the reference mud. Whereases, 76% reduction in filtrate was obtained by adding only 15 ppb of the fine sized PF.