An evaluation of two commercially available swab transport systems, Port-A-Cul (PAC; BBL Microbiology Systems, Cockeysville, Md.) and Anaerobic Specimen Collector (ASC; Becton Dickinson Vacutainer Systems, Rutherford, N.J.), in the recovery of organisms from clinical specimens was done. Fifteen abscesses were drained, and swabs of their contents were placed in the transport systems until they were inoculated for detection of aerobic and anaerobic bacteria. The swabs were plated immediately after collection and after delays of 4, 24, 48, and 72 h. A total of 70 bacterial isolates, 47 anaerobes and 23 aerobes, were recovered from specimens inoculated immediately after collection. The survival of anaerobic bacteria was better in the PAC system than in the ASC system. This was evident as the length of delay in cultivation was extended. At 4 h, 46 anaerobic isolates were recovered in the PAC system, compared with 39 in the ASC system (P less than 0.1). At 24 h, 45 isolates were recovered in the PAC system and 26 isolates were recovered in ASC (P less than 0.001); at 48 h, 40 were recovered in PAC and 15 were recovered in ASC; and at 72 h, 32 were recovered in PAC and 6 were recovered in ASC. There were no differences between the systems in the recovery of aerobic bacteria. These data demonstrate the usefulness of the PAC system in the recovery of anaerobes and the need for quality control of all transport systems for anaerobic bacteria.