It also includes the removal of contaminates which may alter the sample composition and/or damage the analyzer. It is imperative that the gas sample composition is not altered or distorted during the conditioning process. Equations of State (EOS) software programs are useful tools for modeling the behavior of natural gas as it flows through a sample system. With the use of an EOS program one can determine if conditions in a particular sample conditioning system are conducive to the proper sampling of a specific natural gas composition. EOS software can be useful to the engineer or technician during the design, operation, and maintenance of a natural gas sampling system. This paper will discuss the types of information an EOS program can provide and how this can be utilized to solve common sample conditioning problems