The man's symptoms have not been fully analysed but other details have emerged to suggest that the man had contracted the A/H1N1 swine flu virus, deputy manager of Uppsala University Hospital Björn Ragnarsson told Sveriges Radio.
The hospital expects to have conclusive test results on Tuesday.
Uppsala University Hospital has issued a statement confirming that the man died in his home and not been treated at the hospital. He had unspecified symptoms that included fever and a cold.
"Rumours like this arise but there is nothing to specifically suggest that it was the new influenza in this case. But the fact alone that the discussion has arisen means that we have taken tests, for which we do not yet have the results," said Ragnarsson.
The number of cases of swine flu in Sweden rose considerably last week, with 144 new cases confirmed by Sunday. A total of 915 cases have been confirmed since the spring.
"There were an awful lot that came in at the weekend. If we look at the last two weeks we can see a marked increase. On the other hand we had even more cases in week 29. It goes up and down a bit, which makes it difficult to draw any conclusions from the material," said Sandra Rubinova at the Swedish Institute for Infectious Disease Control (Smittskyddsinstitutet).
Statistics show that some 39 percent of swine flu patients in Sweden -- 362 of the 915 recorded cases -- contracted the virus overseas. Cyprus was the source of the largest number of European cases with 108, followed by Spain (89), and the United Kingdom (52), while 131 cases coming from outside the continent, including 90 cases from North America.