Use of biochar as a soil amendment has received a great deal of attention in the past several years. Work has been done to understand the impact of biochar on soil properties and plant growth. We have investigated the effect of biochar samples obtained from different feedstocks on two soils enzymes. Arylamidase catalyzes the hydrolysis of the N-terminal amino acid from peptides, amides or arylamides. β-Glucosidase is involved in the hydrolysis of cellobiose, generating products that are important energy sources for microorganisms in soils. Five biochar samples generated from switchgrass, oak, pine, cedar, and an oak/hickory mixed stand were incubated with soil obtained from the top 15 cm of a grassland Alfisol (at the rate of 10% at room temperature). The pine, switchgrass, and oak/hickory biochar samples significantly reduced the activity of arylamidase and β-glucosidase. The oak and cedar biochar, on the other hand, enhanced the activities of these enzymes. When biochar samples were washed with de-ionized water prior to incubation with the soils samples, the β-glucosidase activity increased for the pine, switchgrass and the oak/hickory biochar samples but activities still remained significantly below the level of the control samples. Washing the cedar and oak biochar samples prior to incubation with soil samples, on the other hand, reduced arylamidase and β-glucosidase activities. The results of the study suggest that the feedstock and pyrolysis processes that were used in biochar production might influence its impact on soil enzymes.