Burkholderia cepacia is well recognized as a potential respiratory pathogen in cystic fibrosis (CF) patients and there is increasing concern about nosocomial acquisition. Environmental contamination with B. cepacia before, during and after physiotherapy was studied in eight adult CF patients. Air was sampled using a surface air sampler, and horizontal surfaces and pillows were sampled with moistened swabs and contact plates, respectively. Thirty-nine (40%) of 97 air samples were positive and counts ranged from 1-63 cfu/m3. Forty-four percent of samples taken after physiotherapy were positive. B. cepacia was not recovered from sinks or horizontal surfaces but the pillows of three patients were positive. B. cepacia is disseminated into the immediate environment by adult CF patients receiving physiotherapy. The potential risk of person-to-person transmission during hospitalization justifies the recommendation that B. cepacia-positive patients should be segregated from other CF patients.