The degree of risk of cross-infection of patients via lung function testing equipment has yet to be quantified. Based on current evidence, elaborate precautions are not justified for the majority of patients attending the laboratory, but attention to appropriate routine cleaning and disinfection protocols is important. Disinfection and sterilization can be achieved by a variety of methods, although chemical methods should be used with caution. Identification of factors increasing the susceptibility or infectivity of particular patients is important in determining appropriate precautions. Where patients are known to be infectious or are immunocompromized, additional precautions such as using a barrier filter may be appropriate. However, because of cost constraints, the routine use of barrier filters is difficult to justify based on current evidence of minimal cross-infection associated with lung function equipment. Until further studies have been conducted to quantify the degree of risk of cross-infection that lung function test equipment poses, the recommendations given in this review provide a practical approach to dealing with this problem.