Cultivation and serological tests for Chlamydia trachomatis were made in a total of 39 male patients (24 married, 11 single, 3 divorced, 1 widower) and their female partners (9 extra-marital, 12 wives) on average 35 years old in both groups. Apart from the clinical diagnosis of non-specific urethritis found in all male patients, 11 patients suffered from other infections (5 from balanitis, 4 from prostatitis, 1 from prepuce infection, 1 from herpetic infection) and subjective disorders. Side by side with clinical diagnosis of cervicitis or in combination with urethritis found in 16 female sexual partners, two of them suffered also from vulvovaginitis, 2 from adnexitis, 1 from candidosis, 1 had dysuric difficulties and 1 female patient was found sterile. 11 women had no subjective problems. The cultivation-tinction technique used in 25 men (14 married, 11 single) and 14 female sexual partners respectively (8 marital and 6 extramarital), positive Chlamydia trachomatics was isolated 21 times (84%) and 9 times (64.3%) respectively. The immunofluorescence technique using monoclonal antibodies applied to 39 men (24 married, 15 single) and 21 female sexual partners respectively, (i. e. 12 marital and 9 extramarital) gave positive results in 29 cases (74.4%) and 16 persons (76.2%) respectively. One patient was homosexual with a positive finding in the urethra and rectum, and, in addition, he was found to have BWR positive with Candida albicans and group B streptococci, however, his serological HIV was negative. The immunoenzymatic test (EIA) showed borderline titres as being positive in men in 28.2% cases and women in 26.3% and high levels (1:128+) in 41.0% in male patients and 21.1 percent in female patients respectively.(ABSTRACT TRUNCATED AT 250 WORDS)