AbstractInfection of humans with Chlamydia trachomatis, a bacterial pathogen with a unique intracellular replication cycle, may cause a variety of clinical manifestations. These are linked to various serovars of the pathogen; trachoma to serovars A-C, oculogenital infections to serovars D-K, and lymphogranuloma venereum to serovars L1-L3. Nineteen serovars are known as human pathogens. The aim of the study was to determine the serovars of 401 C. trachomatis DNA positive extracts from original clinical specimens of patients in Austria including cervical and urethral swabs, urine, genital secretions and conjunctival swabs - collected from 2014 to 2017. Sequence analysis of the omp1 gene, encoding major outer-membrane protein was performed on each sample. In 50.1% of samples serovar E was identified and serovars F, D/Da and G/Ga were found in 16.2%, 9.7% and 9.0%, respectively. Remaining serovars were J (6.0%), K (4.7%), H (2.7%), B/Ba (1.0%), and I/Ia (0.5%). In 19 patients follow up samples could be tested. The majority of C. trachomatis serovars were associated with urogenital tract infections (D-K), however, one of them – serovar B/Ba - is linked to both, ocular and genital tract infection.