OBJECTIVES: 1. To determine the aetiologies of genital ulcers in China. 2. To evaluate a modified WHO syndromic management algorithm for genital ulcer disease (GUD). METHODS: Patients with genital ulcers were enrolled at their first visit to STD clinics in the cities of Shanghai and Chengdu. They were managed according to a modified WHO algorithm for GUD, in which no treatment was given for chancroid. A multiplex polymerase chain reaction was used to detect Treponema pallidum, Herpes simplex and Haemophilus ducreyi. Dark field examination and serology (rapid plasma reagin and Treponema pallidum particle agglutination assay (TPPA) were also used to diagnose syphilis. RESULTS: A total of 227 male and female patients were enrolled. Syphilis alone was diagnosed in 78 (35%), genital herpes alone in 43 (19%), and both infections were present in 28 (12%). No diagnosis was made in 76 (34%). No case of chancroid was identified. The sensitivity of the algorithm for syphilis and herpes was 88.7% and 69.0% respectively, the specificity 95.0% and 50.0%. 12/106 cases of syphilis were incorrectly classified as herpes (11%), and did not receive treatment. More than 97% of patients followed up responded clinically to treatment. CONCLUSION: Further validation and revision of the WHO flowchart for GUD are needed.