Two 28-day experiments with White Leghorn hens were conducted to determine the adverse effect level of ground Cassia obtusifolia seed (coffeeweed) in the diet and to examine the nutrient fortification required to improve depressed performance due to the presence of the seed. In both experiments, five individually caged hens were used for each of the four treatment replications. Treatments for Experiment 1 consisted of a control and six diets with ground C. obtusifolia seed substituted for a filler at levels of 2, 3, 4, 5, 6, and 7%. In Experiment 2, a series of nutritionally fortified (15 to 20% higher nutrient levels) and unfortified diets coupled with seed levels of 0, 4, 6, and 8% for a total of eight treatments was used. Average daily feed intake, hen-day egg production, egg weight, egg specific gravity, and body weight change were determined during each experiment. For Experiment 1, average daily feed consumption was measured every 24 h for the first 3 days. Egg production and feed consumption were significantly reduced by 2% seed in Experiment 1. Within the first 24 h, feed intake was decreased to 37% below that of controls by increasing to the highest seed level. Egg specific gravity dropped significantly below that of controls when hens were fed 5% seed. In Experiment 2, fortification improved feed consumption, hen-day egg production, body weight change, and egg specific gravity over that of birds fed unfortified diets with the same seed level. Finished diets contaminated with 2%, or more, C. obtusifolia seed can cause reduced performance in laying hens, but nutritionally fortifying these diets can help to alleviate depressed performance.