"The victim was saved before be could be embalmed," explained the superintendent in charge of Naivasha district hospital, Dr Joseph Mburu.
He said Paul Mutora, 24, attempted to kill himself by drinking insecticide following a row with his family.
After being rushed to hospital he was given medication that slows the heart, and Mburu said this might have "confused the medical personnel" into believing the patient was dead.
Staff then heard sounds coming from one of the bodies in the mortuary and ran away in terror as he woke up, the doctor said, adding the hospital was investigating the incident.