Full year profits for the Fortis group quadrupled to €2.2bn (£1.5bn), up from €532m (£362m) in 2002, the company reported.
For the group, operating profit increased five-fold, reaching €2.25bn, compared with €430m for the year before.
Operating profit for Fortis' insurance business surged to €996m, an increase of €1.612bn on the €616m loss made in 2002.
The combined ratio for the insurance operations, excluding its Assurant subsidiary, was 99% for the year, down from 103% in 2002. Fortis said this was the result of favourable developments in all branches in Belgium and The Netherlands.
Fortis chief executive Anton van Rossum, said: “We had a good performance in a year that started poorly with a weak economy and low stock markets, but that ended well.
“Operating performance continued to improve thanks to further cost reductions, better interest margins and excellent results at non-life insurance owing to sharply reduced combined ratios.
“The same forces that improved our operating performance in the latter half of 2003 will continue to have a positive impact in 2004 and will compensate for a considerable part of the reduction in net operating profit owing to the sale of 65% of Assurant.
“Barring unforeseen circumstances, we expect that this, together with the already improved markets, will result in a higher net operating profit for the current year.”