Colin and Carole Raeburn, from Bexhill, East Sussex, thought they were unpacking their son Wayne's belongings when they were given the bag but found it actually contained his organs.
The funeral directors Mummery Ltd had been given the bag with Wayne's body after a post-mortem examination at The Conquest Hospital in Hastings.
Mr and Mrs Raeburn expected to find clothes and equipment belonging to Wayne but when Mrs Raeburn reached into the bag, she picked up one of his organs.
"I couldn't understand why the contents felt mushy and thought perhaps that the bag had got wet. I pulled an object which I thought would be Wayne's belt but when I looked at it, I realised it was an organ," she said.
Mrs Raeburn is devastated by the incident, according to her husband. He said: "I have never heard of this before and hope I never hear of it again. We want them to change their procedures and make sure it doesn't happen again to anyone else."
Mrs Raeburn now has regular psychiatric treatment, and will not eat meat or even walk near meat sections in supermarkets.