Two bioluminescence techniques (ATP and total adenylate assay) have been developed and used to enumerate airborne microorganisms collected under controlled conditions of temperature and humidity. The assays were applied to catches from two characterised bioaerosol sampling devices, the Aerojet-General glass cyclone and the IOM Personal Inhalable Aerosol Sampler. Measurement of the adenylate energy charge provided interesting insights into the metabolic state of the collected cells. The total adenylate method produced results in closer agreement with the ATP assay when using the glass cyclone. Results were obtained in 2.5 h and provide a useful method for area workplace monitoring. The application of the assays to a personal sampler have also been demonstrated. More developmental work is required to optimise the washing stages, and achieve similar benefits for the total adenylate assay.