Most physicians and respiratory therapists are knowledgeable of the use of aerosolized drugs, but many are less familiar with the performance characteristics of the nebulizer. In fact, the general opinion is that the performance of the nebulizer is relatively unimportant. However, there is accumulating evidence that the nebulizer itself does make a difference. The decision to replace a good performing nebulizer with a poor performing nebulizer may decrease the delivered dose in half or more. Although this is less important for routine bronchodilator therapy, it may make a big difference with newer aerosolized drugs. Increasingly, the Food and Drug Administration is approving drugs to be used with a specific nebulizer brand and new nebulizer designs are becoming available for use with these drugs. There are several reasons why I think this conference was important. First, new aerosol drug formulations are becoming available and these will require better performing nebulizers. Second, we as clinicians need to be knowledgeable of the newer generations of nebulizers so that we can make informed purchase decisions. Third, and perhaps most important, we must gain an increased appreciation for aerosol therapy as a science. The proceedings of this conference do much to synthesize the current state-of-the art related to new nebulizer systems. This provides, in a complete and cogent manner, the scientific basis for which clinicians can improve their knowledge of the new generation of nebulizers.