Miroslav Satan scored his 300th career goal and Radek Martinek and former Penguins forward Andy Hilbert each had two assists for the Islanders, who snapped a two-game losing streak.
Sidney Crosby and Ryan Whitney each had two assists for the Penguins, who have lost five of six.
Satan scored the game's first goal, his sixth, on a power play 3:38 in. The goal, which also represented his 600th NHL point, came on a one-timed slap shot from the right circle on a pass from defenceman Tom Poti.
Colby Armstrong, Erik Christensen and Mark Recchi had goals for Pittsburgh. Armstrong has three goals this season, all in his last three games against the Islanders.