Met-tRNAf deacylase from reticulocyte ribosomes has been purified to homogeneity. Upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the homogeneous preparation gives a single protein band corresponding to a molecular weight of approximately 67,000. Purified Met-tRNAf deacylase degrades free Met-tRNAf and also Met-tRNAf bound to 40 S ribosomes in the presence of AUG codon but does not degrade Met-tRNAf in the ternary complex, Met-tRNAf.eIF-2.GTP. Purified Met-tRNAf deacylase does not inhibit protein synthesis in reticulocyte lysates at any concentration tested indicating that Met-tRNAf deacylase is not a protein synthesis inhibitor. Antibodies against Met-tRNAf deacylase have been prepared by immunizing a chicken with homogeneous preparation of Met-tRNAf deacylase. Addition of anti-Met-tRNAf deacylase does not have any effect on protein synthesis in reticulocyte lysates indicating that Met-tRNAf deacylase is not required for protein synthesis.