Scor said its 2004 premium income fell 32% from the previous year, as business shrank in the large corporate risks segment.
Gross premiums written for 2004 fell to €2.53bn (£1.7bn) from €3.7bn (£2.5bn) in 2003, according to Scor.
Nonlife reinsurance premium fell 41% to €1.32bn (£900m).
"The decline in premium income is notably due to the reduction indicated in lines written in the large corporate risks sector," the reinsurer said in a statement.
On a regional basis, 54% of Scor's 2004 premium came from Europe. Premiums there fell 29% to €1.37bn. In North America, which accounted for 25% of Scor's premium in 2004, premiums fell 36.8% to €641m.
For the Asia-Pacific region, representing 9% of Scor's 2004 revenue, premiums fell 33.6% to €229m. For the rest of the world, premiums in 2004 fell 28.6% to €285m.