To evaluate the potential for groundwater contamination by viruses, it is essential to understand the processes controlling virus adsorption to soil. Recent laboratory studies have indicated that the degree of viral adsorption is highly type and strain dependent. The purpose of this study was to statistically reexamine earlier data by grouping studied variables into a number of broad categories. The results indicated that different types and strains of viruses can be grouped by their ability to be similarly affected by certain soil characteristics. Viruses could be grouped into two general categories. For group I, the most important factors affecting adsorption were pH, organic matter, and exchangeable iron content of the soil. No studied soil characteristic was found to be significantly associated with adsorption of group II viruses. The implication is that adsorption-elution of group I viruses is more sensitive to certain soil characteristics than that of group II. Certain types of coliphages were found to be better models for some types of enteroviruses than others.