NBA Champion Elden Campbell's Cause of Death Revealed

12/5 10:52 AM PT -- Officials in Florida tell us they received a report of an unresponsive adult male on the beach at around 8 PM on December 1. When they arrived, they found Campbell next to a jet ski on the beach, later pronouncing him dead.

"At this time, there is no foul play suspected, and the death investigation is ongoing."

NBA champion Elden Campbell's cause of death has been revealed ... with officials telling TMZ Sports the former Laker died due to an accidental drowning.

The medical examiner in Florida says Campbell -- who was 57 years old -- was pronounced deceased at 8:03 PM on December 1.

The news of his tragic death was first announced by his former teammates and professional and college organizations.

The 6'11" center spent 15 years in the NBA -- more than half of that run with the Los Angeles Lakers, who drafted Campbell in the first round in 1990.

He also suited up for the Charlotte/New Orleans Hornets, Seattle SuperSonics, New Jersey Nets and Detroit Pistons ... winning a championship with Motor City in 2004.

Campbell's family released a statement on the loss ... saying, "Elden was a man of faith who trusted in his lord and savior Jesus Christ.  Husband, father, brother, cousin and friend."

"He was a man to whom family meant everything -- generous, funny, disciplined and kind, but could shut you down if required. A man of God, he passed doing what he loved; fishing out on the ocean, enjoying his idea of an ideal day."