Technical Abstract: Low infiltration rates constrain effective and economical irrigation on some sandy loam soils on the east side of California's San Joaquin Valley. Polyacrylamide (PAM) has increased soil infiltration in other areas of the U.S., especially where soil erosion is a problem. We applied low concentrations of a high molecular weight, moderately anionic polyacrylamide, the type that is being successfully used for furrow erosion control, in furrow irrigation water on Hanford sandy loam soil. Two years of field scale studies and two years of recirculating infiltrometer tests did not show any increased infiltration with PAM. There was a slight trend for the PAM to reduce infiltration rates, likely due to an increase in "apparent" viscosity when PAM is added to water. We conclude that PAM does not reduce aggregate breakdown and surface seal formation sufficiently for this soil under these conditions to result in increased infiltration.