Eight quinolone-resistant clinical isolates of Neisseria gonorrhoeae were shown to carry mutations in their GyrA proteins. Six isolates had a single amino acid change of serine to phenylalanine at the position corresponding to Ser-83 in Escherichia coli. In addition to the change of serine to phenylalanine, two isolates had another change of aspartic acid to asparagine at the position corresponding to Asp-87 in E. coli.