A sexual transmitted disease, in significant or transient genital lesion. Inguinal buboes and secondary syndromes. Causative organisms are: Chlamydia trachomatis, serotypes LI, LII, and LIII. Incubation period: 5 to 21 days. Common clinical features: Primary Genital Lesions-a papule, shallow ulcer is painless. Secondary manifestation—inguinal lymphadenopathy. As the disease progress, lymph node swelling increases, matted together, softening and fluctuation, multiple abscesses may form, sign of groove may present. Constitutional symptoms: (i) Fever, malaise, anorexia, nausea, vomiting, lassitude, pain in joints. (ii) Variable macular rash. Late manifestations: (a) Scarring, sinus, formations, genital syndrome, anogenital syndrome, genital elephantiasis. (b) Saxophone penis in male, multiple fistulae, rectal vaginal urinary. Investigations: (a) To exclude syphilis, (b) Serological test—VDRI, and (c) Primary lymph node for culture of C. trachomatis: (i) Swab from primary lymph node for culture of C. trachomatis. (ii) Micro immunofluorescence test. Treatment: (i) Tetracycline-Drug of choice 500 mg GID × 14 days – 21 days. (ii) Septran (contrimoxazole 400 mg with trimethoprim 80 mg. 2 gm stat followed by 1 gm × 6 hrs for 10 to 28 days.