The complete nucleotide sequence of rabbit muscle aldolase mRNA has been determined from recombinant cDNA clones and from a primer-extended cDNA synthesis on the mRNA template. The sequence is composed of 1375 nucleotides, exclusive of the poly(A) tails. The 5'-untranslated region contains 62 bases including a potential ribosome-binding site. The 3'-untranslated region is 221 bases long. The remaining 1092 nucleotides are in an open reading frame coding for 364 amino acids. There is a single methionine residue preceding the NH2-terminal proline. The deduced amino acid sequence corrects a number of discrepancies between published structures as well as assignments previously missed. The sequences of the cloned cDNAs suggests there may be microheterogeneity in the messenger RNA population.