A study was conducted to investigate the effect of dietary CP levels on ileal phosphorus (P) digestion in growing pigs. A total of 18 ileal-cannulated pigs (initial BW 44.2 ± 3.2 kg) were used in a duplicated 9 × 3 incomplete Latin Square design, with 9 treatments and 3 7-d experimental periods giving 6 replicates per treatment. The 9 treatments consisted of 1 nitrogen free diet to estimate basal endogenous loss of AA, and 8 corn-soybean meal based diets in a 2 × 4 factorial arrangement, which included 2 CP levels (6.9 or 13.4%) and 4 apparent total-tract digestible P (ATTDP) levels (0.09, 0.16, 0.24, or 0.32%). Soybean meal and mono-calcium phosphate were used to adjust the CP level and ATTDP level, respectively. Limestone was included in diets to maintain the Ca: ATTDP ratio across treatments. Ileal digesta was collected continuously for 10 h on the last 2 d of each 7-d experimental period. The ileal digesta samples were lyophilized and analyzed to calculate ileal digested N and P. Data were analyzed using PROC MIXED procedure of SAS (9.3) and contrasts were used to test the linear and quadratic effects of increasing levels of P within each CP level. In the model, CP and P levels were considered as fixed effects and block (BW) was the random effect. In the low CP groups (6.9%), the ileal digested P were 0.71, 1.16, 1.64, and 2.03 g/kg of DMI for diets that contained 0.09, 0.16, 0.24, and 0.32% ATTDP, and their counterparts in high CP groups (13.4%) were 0.70, 1.54, 2.03, and 1.99 g/kg of DMI. There was a main effect of CP level (P < 0.05) on ileal digested P (g/kg of DMI). The ileal digested P (g/kg of DMI) increased linearly (P < 0.01) with increasing ATTDP levels in low CP groups, but the pattern was linear (P < 0.01) and quadratic (P < 0.01) in high CP groups. In conclusion, this research indicated that the amount of ileal digested P (g/kg of DMI) could be limited by protein deficiency and thus, dietary CP level could affect ileal P digestion.