Unsaturated zone studies to measure the movement and degradation of aldicarb and aldoxycarb residues were conducted in 1983 at seven locations: Maricopa, Arizona; Harrellsville, North Carolina; Blackstone, Virginia; Blissfield, Michigan; Bluecast, Indiana; Pasco, Washington; and Fort Pierce, Florida. The Blissfield and Bluecast studies also included monitoring of tile‐drain water and the Fort Pierce test included shallow ground water analyses. These research studies indicate that aldicarb or aldoxycarb residues will not enter drinking water supplies under agricultural conditions similar to those encountered in these seven field studies. Most, if not all, of the residues will degrade in the unsaturated zone at a rate corresponding to half‐lives of between 0.5 and 2.0 months. The field studies also demonstrate that aldicarb and aldoxycarb residues degrade at about the same rate.