Abstract The need of choline in the diet of mature hens has been adequately reviewed by Welch and Couch (1955) and Burns and Ackerman (1955). In most of the work cited, it was concluded that dietary choline was required for optimum egg production and hatchability. It was also reported that the hen has a limited ability to synthesize choline. The present study, involving two years’ work with 24 lots of 8 to 10 New Hampshire hens each confined to pens with raised wire floors, was conducted to determine whether the level of dietary fat influenced the choline requirement of laying hens. The low-choline basal diet consisted of (%): ground yellow corn 66.5, soybean oil meal 13.0, solvent-extracted meat scraps 2.5; solvent-extracted fish meal 3.0, dried whey 7.5, dehyd. alfalfa meal 5.0, iodized salt 0.475, manganese sulfate 0.025, steamed bone meal 2.0. Vitamins added per pound of diet were as follows: vitamin…