The number of days people spent in hospital beds with flu in 2009 was up 700% on 2008, data showed.
Figures from the NHS Information Centre revealed 33,376 bed days were taken up by people with flu as their main reason for admission, compared to 4,163 in 2008.
The rise was steepest in the final quarter of 2009, with the number of bed days rising to 20,744 between October and December compared to 1,585 in the same period in 2008.
This means the number of bed days was 13 times higher in 2009 than in 2008.
The spread of swine flu in the winter months is thought to have been behind the large rise in hospital admissions.
Of the 20,774 flu admissions between October and December 2009, 5,008 were among under-16s, 6,253 among people aged 17 to 39 and 6,438 were among those aged 40 to 59.
Swine flu hit younger age groups in 2009 than those normally affected by seasonal flu, which is reflected in the figures.
Just 2,543 admissions were in people aged 60 to 79 and another 409 admissions were among people aged over 80.
The data relates to England.
A spokeswoman for the Department of Health said: "A higher level of influenza activity would be expected during a swine flu pandemic and the NHS was ready to cope with the increase in demand."
