Chlamydia trachomatis is the most common cause of sexually transmitted diseases that is not of viral
origin and there is accumulating evidence of a significant role played by this pathogen in causing male factor
infertility. This study thus aimed to determine the prevalence of C. trachomatis among infertile males and to
evaluate their association with fertility status and abnormal semen characteristics. This study included 215
infertile male subjects who visited a major fertility clinic in Warri, Delta state, Nigeria. Forty apparently healthy
males without complaints of infertility were enrolled as controls. Blood samples were collected from patients
aseptically using venous puncture and semen samples were obtained after masturbation. C. trachomatis IgG
antibodies were assayed for in blood specimens using the Dot rapid Assay Kit flow through Ct cassette and
positive samples were further screened with an enzyme immunoassay technique. Semen samples were
analyzed following World Health Organization guidelines. Forty-two (19.5%) out of 215 infertile male subjects
were found sero-positive for C. trachomatis. C. trachomatis was significantly associated with male infertility
when compared to controls (P<0.001). Age groups 20-29 years (43.3%) and 30-39 years (22.1%) significantly had
higher prevalence of C. trachomatis (P<0.001), as compared to age groups 40-49 (7.9%) and > 50 years (3.7%).
Sero-positivity for C. trachomatis antibodies was significantly associated with oligozoospermia (22.5%) and
azospermia (61.5%) than with teratozoospermia (7.3%) and asthenozoospermia (6.3%) (P<0.001). The prevalence
of C. trachomatis among infertile males was high; there was an association between C. trachomatis infection
and poor semen characteristics and infertility. There is need for routine screening for the pathogen in males
with complaints of infertility so as to rule out this potentially correctable/reversible cause of infertility.