Deputies and medics responded to the scene, a mobile home in the 15900 block of Highway 99, at around 4 a.m. after receiving a report of a stabbing, said Snohomish County sheriff's spokeswoman Shari Ireton.
Three victims were found and a 23-year-old man was taken into custody at the scene. The victims and suspect are believed to be roommates.
The two male stabbing victims were taken to Harborview Medical Center, where one was listed in critical condition and the other in serious condition. One of the men had a stab wound to the cheek and the other had injuries to his chest and face, Ireton said.
The 29-year-old woman was treated for a minor neck wound.
All three are expected to survive their injuries.
The suspect is being questioned by police, but so far has provided no explanation to detectives as to the reason for the stabbings, Ireton said. He is being treated for minor wounds before being booked into the Snohomish County jail.