Aminoacyl-tRNA, in which an aminoacyl moiety is attached to the tRNA 3' end, provides the basis for relating an amino acid with an anticodon triplet of the genetic code. There are 20 types of aminoacyl-tRNA, each specific for one amino acid and required for decoding of specific codons on the ribosome. An aminoacyl-tRNA is synthesized by its cognate aminoacyl-tRNA synthetase and is delivered to the ribosome via the elongation factor EF-Tu. Kinetic studies have shown that certain aminoacyl-tRNA synthetases bind to their product aminoacyl-tRNA tightly, thus raising the concern that these tight enzyme-product complexes will inhibit enzyme turnover and delay delivery of the product to the ribosome. The ability of aminoacyl-tRNA synthetases to address this rate-limiting product release problem, and how to maintain the quality of the product without compromising the rate of protein synthesis, will be discussed.