Haleema Iqbal, 35, said she felt ‘disgusted’ following the discovery of the roughly 2inch long (5cm) black insect in the newly bought £17 garment.
She had visited one of the fashion retailers’ recently opened stores in Bradford, West Yorks., on November 2 where she picked out the fluffy grey cardigan.
But when she put her hands through its sleeves back at home, she pulled off what she thought was a clothing sticker and found the dead bug on her arm.
Primark offered Haleema a £50 voucher after she complained about the beetle and said it remained confident of the “high standards and checks” on their goods.
But the healthcare assistant has now vowed never to step foot in another of its stores following her disturbing experience.
Haleema said: “I don’t want to shop there after what’s happened.
“It’s not about whatever voucher they’re going to give me – it’s more how can something like that be in there?
“I didn’t think there was going to be an insect, and then when I’ve obviously pulled on it thinking it’s a tag, there was a beetle.
“I had to flush it down the toilet. I was so disgusted, literally, I was sweating.
“I was panicky. I didn’t know if it was anywhere else. I thought, ‘What if it’s stuck somewhere else’.
“You think to yourself, ‘I need to get into the shower. I felt dirty. I thought something else might be on me as well. It was definitely a traumatizing experience.”
Haleema said she had picked up the cardigan while shopping with her sister at a Primark store near her home on The Broadway, in Bradford.
And following the shocking discovery, she had written to the retailer to share her disgust at what had happened.
But she initially felt “fobbed off” when she was first offered just a £5 voucher and wrote to the firm asking why they had not made further inquiries.
In her email, Haleema wrote: “I’d like to know what happened with this investigation and what you have done about it so this does not happen to anyone again.
“I don’t need a poxy £5 voucher. A beetle was stuck on my arm when I tried this cardigan on and you think a £5 voucher is good customer relations.”
Primark then sent a message back to her saying the matter was being “thoroughly investigated”.
And the firm later offered her a £50 voucher, which she was told she would have to accept within 24 hours.
But Haleema decided not to redeem the offer and said she had no intention of shopping at Primark in the future.
A Primark spokesperson said: “We’re really sorry to hear about the customer’s experience and that she was not happy with how her case was handled.
“We have been in touch with the customer directly and hope that she is satisfied with how this has been resolved.
“There is no way to establish how and when this could have happened, but we remain confident with the high standards and checks we have place with our suppliers.”