Several soil properties are used for identification and classification of soil series, of which color is one of great importance. It depends upon a group of factors as color is particularly sensible to the influence of soil moisture. At the Central Experiment Station in Campinas a study of color was made by employing natural and prepared samples of soil series ranging from dry soil to soil with highest moisture content, whereby the Munsell Soil Color Charts were used for color determination. As for prepared (air-dried and sieved) samples, they may not be given representative colors as of the natural soil samples. Their variation in color is beyond that found in the field. Series of the imperfect group up to the very poorly drained showed the greatest moisture-level influence in the color of natural soil. Commonly these series are admitted to wider variation in color or under some circumstances these properties are not accounted for in identification. The well drained soil color variations derived from moisture level between series specified limits. The field work mapping can be done in this region at any time if the critical point is the color determination. The best moisture condition for soil color determination is that close to the natural conditions. The moisture variation has significant effect on the VALUE except for the «terra roxa» soil (red soil) where the CHROMA shows more sensibility. The CHROMA is the- color component the least affected by moisture variation. In the color determination of the series studied, the authors also noticed the influence of the following factors: environmental light conditions; time of determination; soil color chart conservation and exposure of samples to the air. Since many external conditions affect the results of these determinations, they must be checked carefully, for data comparison.