Two experiments involving 1,152 turkeys were conducted to determine the relative bioavailability of phosphorus of eight phosphates from commercial and experimental sources. The basal diet, composed of 52% dehulled soybean meal and 41% ground yellow corn, contained 1.48% calcium and .44% total phosphorus. Phosphorus from the eight sources was added to the basal diet at levels of .09, .18, or .27% to form 24 diets with a constant calcium content. Each diet was fed to one pen of eight males and eight females from 1 to 4 wk of age in the first experiment and to two pens (one of each sex) of 16 poults/pen from 0 to 4 wk of age in the second experiment. Measurements of percentage ash of the middle toe pooled from all poults within a pen and of average body weight at 4 wk of age provided similar relative phosphorus availability values. With the phosphorus in monocalcium phosphate as the standard set at 100%, phosphorus from two sources of dicalcium phosphate and one source of defluorinated phosphate were found not significantly different in bioavailability (95, 105, and 103%, respectively). Phosphorus in curacao phosphate was only 55% available and in the three experimental defluorinated phosphates, phosphorus was 81, 70, and 87% available. Significant differences in bioavailability between two samples greater than 13 and 18% were found when using toe ash and body weight measurement, respectively.