LRR (Leucine rich repeat) proteins are involved in various biological processes. RACE was used to extend the 5' and 3' unknown sequence of a cDNA-AFLP fragment from cotton ovule, which had sequence similarity to the Arabidopsis thaliana LRR resistance-like (LRR-RL) protein. By joining the sequence of cDNA-AFLP fragment and its 3' and 5' RACE product, it was found that the full-length cDNA (GenBank Accession No. AY040532) of 1259 bp contained an ORF of 987 bp and a putative poly(A) signal. The deduced polypeptide contained 328 amino acids, and consisted of 10 LRRs with extracytoplasmic LRR consensus LXXLXXLXXLXLXXNXGXIPXX. It was demonstrated that the LRR-RL proteins of cotton and A. thaliana were highly homologous, with a distinct structure from other plant LRR proteins, suggesting that LRR-RL proteins belonged to a new LRR protein family. Using 3' RACE, the expression of LRR-RL gene was detected in root, hypocotyls, fiber, and ovules in various developmental stages.