Twenty-four crossbred barrow pigs were used in four replications of six treatments to study the effect of supplementary yeast culture in improving the bioavailability of dietary phosphorus. Pigs were fed corn/soybean diets containing 0.5, 0.4, or 0.3% total phosphorus with or without 0.5% yeast culture. The pigs were fed at 5% of body weight daily in two equal feedings for a seven-day preliminary period followed by a seven-day collection period. The percent apparent dry matter digested, percent apparent absorbed phosphorus, and percent apparent absorbed nitrogen only varied according to the amount of phosphorus in the diet. Yeast culture had no effect on any of these measurements. Serum phosphorus levels in all pigs decreased from beginning to termination of the study with the larger decreases in those pigs receiving less phosphorus in their diet. Supplementing pig diets with yeast culture did not improve bioavailability of dietary phosphorus in this study