Dawn Henry, who worked on a children's ward at Leeds General Infirmary, faces eight misconduct charges.
Ms Henry, 36, from Liversedge, West Yorkshire, was suspended after colleagues complained about her work.
The charges include failing to provide appropriate care and speaking in an inappropriate manner to a colleague.
Ms Henry is also accused of not keeping proper records.
Sarah Page, a barrister for the Nursing and Midwifery Council (NMC), told the council's conduct and competence committee that Ms Henry had left a five-month-old baby in a cot "saturated with urine".
Healthcare assistant Lisa Butlin said she had been shocked by the state in which she found the baby, known as Patient B, when she checked him after Ms Henry's night shift on 21 January 2008.
She told the hearing his clothes and blanket were wet and his cot was marked where urine had been left to dry.
Ms Butlin added she believed he must have been left unchanged for "more than a couple of hours" to get in that state, adding: "Personally, to me you wouldn't leave a baby that long".
'Quite inappropriate'
The hearing was told Patient B had undergone an operation for complications caused by previous abdominal surgery.
Nurse Laura Osborne, who took over from Ms Henry on a day shift, told the committee that on the same shift a seven-year-old boy, who had just had bowel surgery, had been left on the bedpan for "a good couple of hours".
She told the panel she was told to look after the boy, named only as Patient A, and asked Ms Henry if there was anything she needed to know.
She said: "I asked her if there was anything else to add to what I'd been told in handover and she just said 'he's been on a bedpan all night and he needs a bath because he stinks'.
"I thought it was quite inappropriate in front of all the other patients."
Ms Osborne told the hearing she had to clean Patient A and remove the used bedpan.
She said: "He had a red ring around his bottom from where he'd been sat on the bedpan."
Asked how long she thought he had been left, she said: "I would expect a good couple of hours".
The hearing continues.
I asked her if there was anything else to add to what I'd been told in handover and she just said 'he's been on a bedpan all night and he needs a bath because he stinks'
Nurse Laura Osborne
