Wood duck (Aix sponsa) nesting behavior, nest box production and utilization was studied from 1972 to 1974 on three areas in Madison County, Kentucky. Spring arrival of wood ducks occurred in late February and early March. Nest searching began the second week of March. The dates of first laying varied from March 21 to March 23. Egg laying reached a peak in late March. Eggs were deposited at the rate of one egg per day. Average clutch size of all wood duck nests was 12.2 eggs. Average clutch size of normal nests was 11.5 eggs. Clutch size varied from 9 to 20 eggs. One dump nest was discovered. The mean incubation period was 30.3 days. The positions of wood duck eggs changed daily during incubation. A total of 117 wood duck eggs were laid in nest boxes and 77 ducklings left the boxes. Hatching success was 65.8 percent. Three natural cavities containing wood duck nests were located. Mean clutch size for nests in natural cavities was 13.7 eggs. Hatching success was 92.7 percent. The peak hatching period occurred during the third and fourth weeks of May. Brood size decreased from 9.6 ducklings at hatching to 4.3 ducklings at flight stage. No predation of nesting wood ducks or eggs was noted. Competition for nest boxes was severe. Wildlife species occupied 91.4 percent of available nest boxes in 1972 and 73.6 percent in 1973. The starling (Sturnus vulgaris) was the most serious nest competitor. Wood duck usage of nest boxes was low but increased from two nests (7.2 percent) in 1972 to eight nests (20.5 percent) in 1973. This increase was due to improved maintenance and relocation of nest boxes.