A collection of 32 stroma-targeting chloroplast transit peptides with known cleavage sites have been analysed in terms of amino acid preferences in the vicinity of the processing site. A loosely conserved consensus motif (Val/Ile)-X-(Ala/Cys) decreases Ala is found in the majority of the transit peptides. About 30% of the sequences have a perfect match to the consensus. When such a match is found, there is a 90% probability that it specifies the correct cleavage site.