The ex-"NYPD Blue" actor's autopsy results were released Tuesday by the Los Angeles County Medical Examiner's Office -- and his cause of death is attributed to fentanyl toxicity. The manner is listed as accidental, and the place of his death reads ... "residence."

Remember, Majors passed away while staying at a homeless housing facility in L.A. back in February -- and we were told at the time that fentanyl was suspected to be in play.

It's a tragic end to Majors' story ... who was a successful actor in the early years of his life. He famously played Theo Sipowicz on the famed ABC drama series, starring in 48 episodes.

In addition to "NYPD Blue," Majors had worked on other big shows like "Providence," "How I Met Your Mother," "ER," "Hercules," "Threshold," "According to Jim," 'NCIS,' "American Dad!," "Desperate Housewives" and others. He'd also been in a handful of memorable movies.

His acting career appears to have slowed down in the late 2000s ... Majors doesn't have credit post-2009. The family released an emotional statement at the time of his death, remembering the best parts of his life.

The statement read, in part ... "Austin was the kind of son, brother, grandson, and nephew that made us proud and we will miss him deeply forever."

Majors was just 27.