The new chief executive of the Medical Research Council will tell MPs the UK must increase medical research funding to maintain its world lead.
The UK has a high research reputation
Professor Colin Blakemore will say the UK spends less public money on research than many developed countries.
Currently the MRC can fund only a quarter of all research applications.
Professor Blakemore will give evidence to the Commons Science and Technology Committee on Monday.
The amount spent on medical research has increased by a third in real terms over the past five years - more than any other area of research.
And MPs on the committee recently criticised the MRC for spending too much on expensive, highly ambitious projects and not enough on smaller programmes.
But Professor Blakemore will argue that he needs more money to fund both, particularly with promising areas of research opening up as a result of the human genome project and stem cell technology.
Other priority areas include research into brain sciences and mental health, new approaches to treating infections and studying the links between health and behaviour.
He said: "Many of the treatments and preventive measures used in UK health care have been developed from MRC-funded research.
"We aim to continue to fund the best research with the potential to improve human health in areas where the burden of disease is most significant.
"But the biggest challenge facing medical research in the UK is the shortage of funding in relation to the opportunities for making significant advances that will ultimately lead to better health and wealth.
"There are so many good ideas, but not enough funds to support them.
"In comparison to many other developed countries, the UK spends less public funds on medical research.
"For example, the National Institutes of Health in the United States spends nearly 40 times as much as the MRC receives in grant-in aid and about eight times, per capita of the population."
Professor Blakemore will also point to the challenges facing medical research such as obtaining consent for new uses of existing human tissue, threats to primate research, and EU legislation on clinical trials and stem cells.
He will also stress the need to maintain public trust in science through a sustained and honest dialogue about what science involves and what it can, and cannot, deliver.