The report describes how to install and use the Geo-EAS (Geostatistical Environmental Assessment Software) software package on an IBM-PC compatible computer system. A detailed example is provided showing how to use the software to conduct a geostatistical analysis of a data set. Thirteen Geo-EAS programs are documented. The principal functions of the package are the production of 2-dimensional grids and contour maps of interpolated (kriged) estimates from sample data. Other functions include data preparation, data maps, univariate statistics, scatter plots/linear regression, and variogram computation and model fitting. Extensive use of screen graphics such as maps, histograms, scatter plots and variograms help the user search for patterns, correlations, and problems in a data set. Data maps, contour maps, and scatter plots can be plotted on an HP compatible pen plotter. Individual programs can be run independently; the statistics and graphics routines may prove useful even when a full geostatistical study is not appropriate. For ease of use, the programs are controlled interactively through screen menus, and use simple ASCII data files.