Coffea arabica and Pithecellobium carbonarium leaf litter was added to Alonso soil (Oxic Dystrudepts) to asses the effect on extractable Al3+. Four leaf litter treatments were evaluated: 1) No leaf litter (Check); 2) three percent Coffea arabica leaf litter; 3) three percent Pithecellobium carbonarium leaf litter; and 4) three percent of a 1:1 Coffea Arabica:Pithecellobium carbonarium leaf litter mixture. Six grams of leaf litter were mixed with 200 g of soil collected at 0-20 and 20-40 cm depths. The soil was moist with 60 ml of distilled water, placed on glass jars and incubated at room temperature. Each treatment was replicated four times and arranged in a complete randomized block design. Exchangeable Al3+ was extracted with 1 NKCl , extractable Al3+ weakly bound to soil organic matter was extracted with 0.33 M LaCl3 and extractable Al3+ strongly bound to soil organic matter was extracted 0.5 M CuCl2. The highest soil exchangeable Al3+ , 1.43 cmolc kg-1, was observed on the check treatment, followed by the Pithecellobium leaf litter with 1.29 cmolc kg-1, the 1:1 mixture with 0.59 cmolc kg-1 and the coffee leaf litter with 0.31 cmolc kg-1. Significantly larger amounts of Al3+ were extracted with 0.33 M LaCl3 and 0.5 M CuCl2 than with 1 N KCl, a clear indication of the importance of organic matter in Al3+ complexation reactions. The highest pH (4.29) was observed on coffee litter treated samples, the check showed a pH of 4.00, the 1:1 leaf litter showed a pH of 3.94 and the Pithecellobium leaf litter showed a pH of 3.90. The significant decrease in exchangeable Al3+ with the addition of Coffea and Pithecellobium leaf litter, even in cases where a decrease in soil pH was observed, indicates that other mechanisms, besides pH, are involved in the neutralization of extractable Al3+fractions.