Cardiff and Vale Health board says it cannot find any evidence to support a former patient's claims that she was inappropriately touched by disgraced broadcaster Jimmy Savile in the 1960s.
An investigation was carried out at 28 NHS hospitals, including the Cardiff Royal Infirmary.
While a series of reports published today found Savile subjected patients in healthcare institutions across the country to "truly awful" sexual abuse for more than four decades, the Cardiff Royal Infirmary allegation could not be substantiated.
The woman reported an incident she said happened there when she was in her early 20s.
Her allegation, according to the report is that: "At midnight on New Year's Eve, Matron (or the night sister) attended the ward with three men. Whilst the nurse stood at the end of the ward with the two men talking, Patient A was approached by an individual believed to be Jimmy Savile.
"He was dressed in a tracksuit and had long blond hair. He was wearing jewellery and was walking quickly around the ward. He took the patient's left hand and started to kiss it and moved up kissing her arm whilst leaning on the bed. When he got near her shoulder/armpit she felt very uncomfortable and pulled the sheets over herself."
Ruth Walker, director of nursing for Cardiff and Vale University Health Board, said: "The health board has conducted an exhaustive investigation into this one case from the 1960s, reviewing hundreds of archived documents over a period going back 50 years and interviewing staff who worked at Cardiff Royal Infirmary at the time.
"Those efforts have found no documented evidence to support the patient's account or place Jimmy Savile at the hospital during the time in question.
"Whilst we have no reason to disbelieve the patient, the health board has examined every possible avenue of inquiry and, given the patient's request not to be involved in any further investigations, there is no additional action that can be taken."
Investigators believe the true scale of Savile's abuse in UK healthcare institutions has been under-reported.