The distribution of Chlamydia trachomatis serovars among 157 heterosexual male patients with urethritis and the presence of coinfections with other sexually transmitted infections were studied. One hundred seventeen (74.5%) patients, with a mean age of 33.7 years, were Italians, whereas 40 (25.5%) were immigrants coming from eastern European countries, Africa, and South America. All the immigrants and 82 (70.0%) Italian patients reported sex with prostitutes. Out of 157 patients, 73 (46.5%) were found positive for C. trachomatis in urethral secretions and eight different C. trachomatis serovars were identified. The most common serovars were E (n = 18; 24.7%), D (n = 15; 20.5%), G (n = 14;19.2%), and F (n = 12; 16.4%). The sequencing data showed a high degree of conservation of the omp1 gene. Thirty-six (46.7%) out of the 73 C. trachomatis-positive patients were coinfected with another sexually transmitted infection. The most common coinfection was gonorrhoea detected in 22 (30.1%) patients, followed by condyloma in eight (8.2%) patients, syphilis in five (6.8%), and HIV in three (4.1%).