cDNA clones of guinea pig neutrophil 33 kDa protein, a lipocortin like-protein, were isolated from two lambda gt10 libraries and one primer-extended lambda gt10 library of guinea pig neutrophils using synthetic oligonucleotide probes or cDNA fragment probe. The cDNA consists of 1389 nucleotides, and contains 1038 nucleotides encoding 346 amino acids of 33 kDa protein and a poly(A) tail. The deduced amino acid sequence shows high homology with those of lipocortin 1 from human U937 cells (89% homology) and rat lung (86%).