cDNA clones encoding human neurotrypsin have been isolated from a human fetal brain cDNA library using a PCR-amplified probe. The assembled cDNA sequence contains a 2625 bp open reading frame encoding a multidomain serine protease with an overall sequence identity of 82.5% to murine neurotrypsin. Surprisingly, the human neurotrypsin exhibits an additional scavenger receptor cysteine-rich repeat.