Bromus tectorum (cheatgrass) has been an invasive species in the Intermountain West of the United States for approximately 100 years. The species is extremely adaptive to fire disturbed environments in the western US and out-competes many native species once it establishes at a site. While it provides a forage for grazing animals the quality of the forage is considered lower than natives in the area. We investigated changes in physical and chemical properties in two surface soils, over two decades, following cheatgrass establishment by wildland fire (Artemisia tridentata [Big Basin sagebrush] was the predominate vegetation prior to fire). Two soils (US soil taxonomy natriargids and haplodurids) representing a majority of the land area were chosen for analysis. In addition, an unburned sagebrush control (natriargid only) was also sampled in order to compare changes due to B. tectorum. All B. tectorum invaded sites had experienced one fire, which resulted in quick colonization with B. tectorum following the fire. All sites consist of well drained soils that formed in aeolian materials with some influence from volcanic ash. Aeolian materials are typically overlying alluvium from mixed rock sources. All sites are located on fan piedmonts and fan remnants. Mean annual precipitation is 23 cm and mean annual temperature is 9 ºC. Slopes across all sites are approximately 2% (range of 2-5%). Four sites for each soil were sampled, spanning a time period of 20 years. At each site, 3 holes were sampled at 0-5 cm, 5-10 cm, and 10-15 cm. Soils were examined in the field for aggregate stability and surface strength (pocket penetrometer) and in the laboratory for particle size analysis, bulk density, exchangeable cations (Ca, Mg, Na, K Fe, and Mn), Total %C and %N, and exchangeable phosphorus. Both soils invaded by B. tectorum were found to progressively accumulate organic matter, calcium and magnesium over time. Haplodurids saw progressive increases in soil pH with time while little change was evident in natriargids. Little change in natriargid soil pH is believed to be due to the high clay content of these soils, which provides a high buffering capacity. Total % soil N increased over time for natriargids while no trend was seen with haplodurids. Natriargids were found to accumulate silt over time while haplodurids saw a trend in decreasing silt over time. Particle size differences are likely the result of aeolian accumulated fines caught due to increased surface area in cheatgrass areas as compared to sagebrush areas. Comparisons between B. tectorum areas and the control indicate that A. tridentata sites have a higher sand content and tend to have a lower C:N ratio than cheatgrass areas. A. tridentata sites have the lowest %Total C, the lowest %Total N, and the lowest phosphorus. Results suggest that while changes in soils may be partly due to fire, B. tectorum over time physically and chemically quickly alters soils once established, which likely further promotes it's establishment over native vegetation.