Pooled specimens from the urethra and cervix accounted for 97% of 101 positive chlamydial isolations in 332 women, and this yield compared favourably with the individual yield from either the urethra (77%) or the cervix (88%). Pooling specimens caused no apparent increase in toxicity to the cell culture system. These results indicate the advantages, in terms of higher yield and no higher cost, of combining the urethral and cervical specimens in one container.