The objective of the current study was to evaluate the utilization of calcium (Ca) and phosphorus (P) in growing sheep consuming increasing amounts of dicalcium phosphate. Eighteen growing sheep, aged 8 months, were fed a basal diet supplemented with 0, 12·5 and 25 g of dicalcium phosphate/day. During the experiment, animals were injected intravenously with 7·4 MBq of 45Ca and 32P and samples of plasma, faeces and urine were subsequently taken daily for 1 week after injection. Rumen fluid was sampled on days 4-7 after injection. Specific radioactivity in plasma and in faeces were used to determine true absorption of Ca and P, whereas plasmatic and ruminal specific radio-activities were used to determine endogenous P flow into the rumen and turnover time of rumen P. Increasing dicalcium phosphate intake led to linear increases in faecal excretion of endogenous Ca and P (P<0·05), suggesting that surpluses of ingested Ca and P were voided through secretion to the gut. True absorption coefficients for 0, 12·5 and 25 g of dicalcium phosphate ingested daily were 0·54, 0·41 and 0·38 for Ca, and 0·66, 0·62 and 0·64 for P, respectively. Flows of endogenous P into the rumen increased linearly and ruminal turnover time of P decreased linearly (P<0·01) as P intake was increased. Concentrations of Ca and P in bone were not affected by the increased amounts of these minerals ingested (P<0·05). In conclusion, increasing ingestion of dicalcium phosphate increases faecal excretion of Ca and P, thus decreasing the efficiency of utilization of both minerals. Moreover, increasing levels of dietary P increased endogenous P excretion, contributing to the amount of P disposed of in the environment. © 2012 Cambridge University Press.