An assay was conducted with the aim to evaluate the phosphorus fixation capacity of A1 (0-22cm), A3 (22-56em) and B22 (155-200cm horizons of a "Roxo Latossol". Also, the "X" value of WAUGH & FITTS (1966) of the three horizons was determinated. The main results are showed below : 1 - The phosphorus fixation capacity of the three horizons are in the following rank: B22 > A3 > A1. 2 - The "X" value are: 350 ppm (B22 horizon), 225 ppm (A3 horizon) and 175 ppm (A1 horizon). 3 - Correlations were found at the level of 1'% between added R and fixed R by the studied horizons.