The efficiency of the mycorrhizal fungi Cenococcum graniforme and Suillus luteus on young seedlings of Pinus radiata for phosphorus uptake from different sources was investigated using 32P. There was a stimulatory effect of mycorrhizas with Suillus luteus on uptake of phosphorus. Cenococcum graniforme had a stimulatory effect on incorporation of 32P only when most of the phosphorus was in organic form. In the other conditions this symbiont had an inhibitory effect. There was a greater accumulation of phosphate in the roots than in the green parts of the seedlings.