The author reviews the more important studies on the laboratory diagnosis of gonococcal infections published since 1964. The most significant new developments are the use (a) of fluorescent antibody techniques and (b) of selective media for the identification and isolation of Neisseria (N.) gonorrhoeae. The sensitivity and specificity of culture methods and of the direct "delayed" fluorescent antibody technique (FAT), both at their best, are very similar, but the FAT allows for more rapid reporting. The results of the direct "undelayed" FAT can be given even more rapidly, but, especially with specimens from women, it is less sensitive than culture or the direct "delayed" FAT. The use of a selective medium facilitates the recognition and identification of N. gonorrhoeae, but the advantage of a selective medium over a non-selective medium depends very much on the skill of the technical personnel involved. One disadvantage is the existence of gonococcal strains that are very sensitive to the antibiotics used hitherto for the suppression of Gram-positive contaminants. Ideally, selective medium should be used in combination with the direct "delayed" FAT after growth on non-selective medium. Other new achievements are a complete, chemically defined, protein-free liquid medium for the culture of fastidious Neisseriae; a commercially available chemically defined enrichment supplement; and a new specimen-transport kit using Stuart's medium.The author also reviews recent reports which suggest that the in vitro sensitivity of N. gonorrhoeae to penicillin and other antibiotics used for treating gonorrhoea is generally decreasing; however, some reports of increasing sensitivity have lately come from Scandinavia.