A roommate tiff turned bloody in the Mission district Wednesday, cops said.

One of two 27-year-old men living together slashed the other in the neck with a three-inch knife after an argument, police said.

The pair lives in the 3400 block of Mission Street, and cops responded to the residence around 9:40 p.m., police said.

Cops arrested the suspected attacker, they said.

The knife-slashed roommate was transported to the hospital, where he was treated for non-life-threatening injuries.

rnagle@sfexaminer.com