An almost complete cDNA copy of human growth hormone has been cloned and sequenced. The nucleotide sequence confirms the known protein sequence and predicts the sequence of a precursor region of 26 amino acids. We have compared the nucleotide sequence to that for the homolgous proteins, rat growth hormone and human chorionic somatomammotropin (Seeburg et al. and Shine et al., Nature 270, 486 (1977)). There appears to be evolutionary conservation of mRNA sequence features not related to protein structure.