The objectives of the study were (1) to determine principal soil factors and conditions influencing the interflow process and (2) to develop relationships leading to quantitative predictions of interflow rates and volumes based on measurable soil characteristics. A field experiment was conducted which included measurements of precipitation, surface runoff, interflow runoff, and soil moisture content on a vegetated plot. Soil moisture tension was also measured at six depths during periods of wet-soil conditions. Interflow was observed twelve times during an eighteen month period. During each event, the topsoil was at or near saturation, indicating that interflow is primarily a saturated-flow phenomenon.