In 1994 Chlamydia trachomatis specimens from 175 men and 135 women attending a clinic for treatment of sexually transmitted disease were genotyped by polymerase chain reaction-based restriction fragment length polymorphism of the omp1 gene. Information about the patients was collected at their initial visit. The associations between C. trachomatis genotype and patients' self-reported symptoms, clinical signs, and characteristics were studied. Genotypes E, F, and D/D-predominated (men: 71%; women: 60%). Five specimens (1.6%) showed evidence of mixed infections. Among men, complaints of urethral discharge and dysuria were most commonly associated with genotypes H and J (100% vs. 59%-68% for the other genotypes; P = .03); in addition, > or = 10 leukocytes per microscopic field were least often observed for genotypes G/Ga (19% vs. 59%-65% for the other genotypes; P = .01). Women's reports of lower abdominal pain were more often associated with F, G group genotypes (32%) than with B-complex (6%) or C-complex (13%) genotypes (P = .02). Certain symptoms of genital C. trachomatis infection were related to the infecting genotype. Further work will be necessary and should involve markers of the host immune response.