During the large scale partial sequencing of human heart cDNA clones, a novel clone which is very similar to the rat ribosomal protein L29 in both DNA and amino acid sequences was found. The cDNA encodes a protein with a deduced molecular weight of 17751 (159 aa). It shows 80.4% homology to protein L29 from the large ribosomal subunit of rat and is related to yeast YL43. The putative protein was named human ribosomal protein L29 (hRPL29). hRPL29 has a large excess of basic residues over acidic ones. The large amount of charged residues makes the protein very hydrophilic and the protein has a deduced pI of 12.16. Internal repeats have been characterised in many ribosomal proteins and a tandem repeat of KAKAKAKA was found to be unique to hRPL29. Analysis of gene organisation by Southern blotting shows that of the approximate 10 copies of hrpL29, all but one are pseudogenes. Northern analysis indicated that the mRNA that encodes human L29 is approx. 800 base pairs in length. An intron of hrpL29 has also been cloned and sequenced by polymerase chain reaction using human genomic DNA as the template.