A 38-year-old man who had sex with men, presented at the outpatient department for Sexually Transmitted Diseases in Amsterdam with a painful, red, fluctuating swelling in the left groin and general discomfort. He had been sexually active in the population of men who have sex with men, in which an anorectal lymphogranuloma venereum (LGV) epidemic has recently been discovered. Unlike other cases where there was anorectal involvement, this patient was the first case of LGV with the classical inguinal presentation although he had not visited the tropics where the inguinal form of LGV occurs as an STD. Routine investigation using PCR on material from urethra and rectum and from the urine, repeatedly failed to detect LGV. However, PCR on pus aspirated from the enlarged lymph node demonstrated Chlamydia trachomatis serovar type L2. Treatment with doxycycline 100 mg twice daily was started. This case illustrates that routine analysis from urethra and rectum and of urine may fail to detect LGV. Furthermore, this case of a patient who probably had LGV initially in the urethra may be the missing link in explaining the route of transmission of the anorectal LGV epidemic.