Miami became the third team in the NBA this season to reach 30 victories, joining Oklahoma City and Chicago. It was a close call, however, with Atlanta twice closing to within a point in the final minute.
Vladimir Radmanovic cut the Hawks' deficit to one by making a layup with 7 seconds remaining, but Wade boosted the advantage back to three with two foul shots.
Jannero Pargo missed a 3-point try that would have sent the game into overtime.
LeBron James had 31 points and 11 rebounds for the Heat, who have won two games in as many nights after dropping two in a row. Wade added 18 points, nine rebounds and six assists.
Josh Smith scored 23 for Atlanta, which had won three straight.