This experiment was undertaken to investigate the effect of the supplementary artificial light on laying of ducks by ate following method and the results obtained were a follows: 30 female ducks of Khaki-Campbell Breed were devided into 2 groups and one of them was submitted to 14 hr. light per day under 60 watt bulb from 21st. Sept. 1963 through 31st. Mar. 1964, and the other one was untreated control. Both of them were full feeded with laying chicken ration. The treated group was not only highly significant on the rate of laying but was also more profitable in the egg-feed economy than the control.