I In an operation of drilling many found problems often arise. Hence need planning use of drilling mud and correct drilling can proceed smoothly. Problems that often occurs in the operations of drilling are: piped stucked because of develop formation shale, pack off, lost circulation, etc. On this final assignments will be discussed the use of LCM and influence of LCM use to the propertise drilling mud. Drilling used on this research is KCL polimer mud and propertise will be test: mud weight, PV (plastic viscosity), YP (yield point), gel strength 10 second, gel strength 10 minute, API filtrate, API mud cake, HTHP filtrate, HTHP mud cake, pH, % liquid content, and % solid content. For test influence addition LCM to the propertise mud KCL polimer used three types of KCL polimer mud with different mud weight, are: KCL polimer with 10 ppg weight, KCL polimer with 12 ppg weight, and KCL polimer with 13,5 ppg weight. On the other hand for every mud weight make another five kinds of mud. First mud make original without LCM addition, second mud create and added 5 ppb LCM, third mud create and added 10 ppb LCM, fourth mud create and added 20 ppb LCM, and fifth mud create and added 25 ppb LCM. For all the mud formulation in hot rolled at the 250 degrees farenheit temperature for 16 hours.