A university college with a "distinguished history" in chemistry research may have to shut the department because of a falling number of students.
The chemistry department is losing more than £1.25m a year
King's College London says it can no longer afford to run the department in its present form.
Researchers at King's laid the foundations for the discovery of DNA 50 years ago.
In a statement, the college said the chemistry department was losing more than £1.25m a year.
A decision on the department's future would be made "in months rather than weeks", it said.
In the last 10 years accepted applications for chemistry first degrees had fallen by more than a quarter according to the Royal Society, the UK's leading scientific institution.
This strikes at the heart of chemistry in the UK at a time when the government is investing in the science infrastructure
Dr David Giarchardi, Royal Society of Chemistry
Royal Society vice-president Professor John Enderby said: "Other science and engineering subjects, such as biology, have shown a similar decline in popularity.
"It is something we should all be concerned about because the UK has a proud tradition in chemistry, with three British Nobel Prize winners in the subject over the last 10 years."
The college said recruitment of undergraduate and PhD chemistry students would still go on for the 2003/4 academic year.
A management group would look into ways of retaining a "high quality research programme".
The statement said: "The College acknowledges the distinguished history of the department and the excellent research and teaching profile of its current staff, and recognises there is a national problem in recruiting students to chemistry and funding research at the highest level."
In 1951 at King's Dr Rosalind Franklin took the first X-ray photographs of the structure of DNA.
That led to the discovery of DNA's double helix structure by James Watson and Francis Crick in 1953.
Dr David Giarchardi of the Royal Society of Chemistry said he was "appalled" at the threat of closure.
"This strikes at the heart of chemistry in the UK at a time when the government is investing in the science infrastructure and at a time when the chemical sciences are of huge importance in progressing the health and wealth of the nation."