Emma Brailsford was disgusted when her partner Scott Rumblow broke open a piece of chicken and found some form of offal inside.The pair, of Withernsea, had popped to the fast food restaurant in Brighton Street, Hull, on their way home from the city.
"At first, we thought it was a brain, as it was all wrinkly," said Emma.
"However, with it being from a chest cavity of a chicken, it was more likely to be a lung or heart.
"We checked all four pieces of chicken and the same item of offal was present in all but one piece.
"This is absolutely disgusting."
The pair had bought a Wicked Variety Bucket costing £17.99, which includes original chicken, mini fillets, hot wings, dips and fries.
KFC, whose slogan is "So Good", has apologised and, after investigating the photographs, believe it may be a kidney.
A spokesman said the company has suspended two members of staff pending an investigation and are retraining their cooks in the restaurant.
"My partner and I felt physically sick," said Ms Brailsford, a customer service officer at the Pavilion Leisure Centre in Withernsea.
"It hasn't just put me off KFC for life but I don't know if I will ever eat chicken again.
"We showed the manageress and she was horrified.
"She did not know what it was and apologised.
"She asked if I wanted another meal, which we didn't. We got a refund."
Emma took a photograph of the chicken and has even kept a piece, which is going to be sent off to KFC.
"We want to warn people to look at what they eat. I've shown all my friends and my mum the picture and they have all been horrified."
KFC hit the national newspaper headlines earlier on this year when a 19-year-old in a Colchester found something similar when eating a Gladiator box meal.
Emma said: "A friend showed me a copy of the article. I couldn't believe it happened in the past so recently.
"You shouldn't be worried with what is in the food with the amount you pay."
A spokesman for the franchisee, which operates KFC in Hull, said: "We are really sorry for Ms Brailsford's experience.
"We sell 200 million pieces of chicken every year and always try to ensure the highest standards in every restaurant and, after a thorough investigation, it appears that on this occasion, a giblet was not removed in the preparation process.
"While there was no health risk, we agree it was unsightly.
"We have apologised to Ms Brailsford and will be providing her with a gesture of goodwill.
"We take food quality incredibly seriously and have suspended two employees pending an investigation, and we will also be retraining our cooks in the restaurant to
ensure this doesn't happen again."
