Heat exchangers are often composed of Al fins and Cu tubes. When they are used in highly corrosive environments they can suffer from corrosion of different type. The effect of different environments on exchangers of different design was studied by standard accelerated corrosion tests. Exchangers with fins made from several Al alloys and both with Cu and Al tubes were tested. It was found that the contact between Al fins and Cu tubes is the most critical site from corrosion point of view. Organic coatings on Al fins were proved to have preventive effect against corrosion, but their effectiveness depends on coating thickness and integrity. Exchangers with Al fins and Al tubes exhibit the best corrosion resistance.