There have been five cases of items being left in patients over the past three years, figures obtained by the Mail reveal.
In 2009, one foreign object was left inside following an operation while there were three last year, according to the Hull and East Yorkshire Hospitals NHS Trust.
There were no such cases in 2010 and one case this year.
The majority of the objects left inside following operations are medical items such as tissue forceps, suture needle, gauze swab and a nasal tampon.
There is nothing to suggest the mistakes led to any serious harm for the patients concerned.