Sophie Nutt, 26, says she has waited 14 years to take part in the event after father, Simon, died of pancreatic cancer in 2008.
Almost 9,000 people die of the disease every year, with only 7 per cent surviving more than five years after diagnosis.
Ms Nutt said that pancreatic cancer research had been historically underfunded, making up just 2.1 per cent of the UK Cancer Research budget.
She added that since losing her father, she wanted to raise awareness of the disease, to help save others before it’s too late.
This year’s London Marathon takes place on October 2, a month before World Pancreatic Cancer Day in November.
Sophie said: “I’ve always known I’d like to do something huge to raise money for Pancreatic Cancer UK, who do incredible work in supporting those impacted by the disease.
“Well, you don’t get much bigger than the London Marathon!”
After being inspired by last year’s London Marathon, the Tunbridge Wells-based 26-year-old has now secured a charity place to run and is in the middle of a 16-week plan ahead of race day.
She hopes to raise £2,500 for Pancreatic Cancer UK, which invests in specialist research, campaigns for faster diagnosis and provides on-hand support to those impacted through a free phone support line staffed by nurses.
Sophie admitted: “This is a massive challenge, and it will definitely be tough (anyone that knows me, knows I’m not a naturally gifted runner) but I have no doubt that it will be worth it.”
Sue Collins, fundraising director for Pancreatic Cancer UK, said: “We are delighted Sophie is supporting us and we would like to wish her the very best of luck.
“The funds raised by Sophie’s endeavour will help to offer support to patients and families, through being invested in vital research to help see the breakthroughs urgently needed and also provide a voice for everyone affected by the disease.”