The stock exchange's broad OMXS index closed down 1.6 percent and is now down 4.7 percent since the turn of the year.
On the large-cap OMXS30 list, nearly all stocks were in the red.
The worst performer was the defense group Saab, which fell 4.5 percent, followed by the mining giant Boliden, down 3.4 percent.
Against the trend, heat pump manufacturer Nibe rose 6.4 percent.
The situation on the stock markets in Europe was about as bleak as in Sweden - London, Paris and Frankfurt all closed down.
The Stockholm Stock Exchange was green at times, but reports that the US is sending more forces to the Middle East made many worry that the US and Israel's war against Iran may continue for a long time.
The oil price is not yet at its recent peak levels, but a barrel of Brent oil was close to $110 at 5:30 p.m., a relatively high price.
