The population studied was composed of 174 consenting women seen at the Male Infertility Center in Toulouse, France, from November 1997 to July 1998. The date of their last sexual intercourse was accurately known. Three glass slides were prepared from each swab. They were air dried, fixed in alcohol and ether, and stained with either hematoxylin-eosin, nuclear fast red and picroindigocarmine (Christmas-tree stain), or alkaline fuchsin. All slides were screened microscopically with a magnification X40 on 100 microscopic fields, and the mean number of spermatozoa per field was counted. In addition to the swabs, characteristics of the sperm (volume, spermatozoa count) of the partner were noted during a previous outpatient visit, and the gynecologist observed the characteristics of the cervicovaginal secretions (cervical dilatation, quantity and quality of mucus) after pelvic speculum examination, using a three-grade classification system. Compared with alkaline fuchsin, Christmas tree and hematoxylin-eosin stains appeared to be gold standard cytological methods for detecting spermatozoa. Their level of detection seemed similar, although Christmas-tree stain had the advantage of being easier to read. One major factor that influenced spermatozoa detection was the interval between ejaculation and swab collection. No spermatozoa were found after three days. The second major factor was sperm volume. 4 figures and 22 references