Half-cystine peptides were isolated from the enzymatic digest of reduced and carbamidomethylated alpaca growth hormone. From their amino acid composition and determination of the end terminal residues we propose the amino acid sequence around the two disulphide bridges, partially based on homology with other mammalian growth hormones. The proposed sequence is identical to that of equine growth hormone and very similar to those of rat, bovine and ovine hormones.