Background: Gonorrhoea is the second most commonly diagnosed bacterial STI in the UK, 22 549 cases seen in GUM clinics in 2001. Neisseria gonorrhoeae has developed resistance to antimicrobials including penicillin and ciprofloxacin, which are both recommended as first line treatment. The GRASP programme was established in 2000 to provide enhanced surveillance of antimicrobial resistance. Objective: To describe the prevalence, geographic distribution, and determinants of gonococcal antimicrobial resistance. Methods: Between July and August 2001, gonococcal isolates from 26 sentinel GUM clinics were collected for antimicrobial susceptibility testing at one of two reference laboratories. The minimum inhibitory concentration of five antimicrobials were determined. Clinical, demographic, and behavioural data were collected from the patient records. Results: 2666 isolates were collected, of which 3.1% showed resistance to ciprofloxacin (≥1 mg/l) compared with 2.1% in 2000. Increased risk of ciprofloxacin resistance was seen in heterosexual males (p <0.05), and individuals having sexual contact abroad (p <0.0005). 8.1% of isolates were penicillin resistant (≥1 mg/l or β-lactamase positive) versus 9.2% in 2000. 32.5% were resistant to tetracycline versus 37.6% in 2000. Ciprofloxacin resistance was heterogeneously distributed across regions (p <0.0005), with high prevalences seen in the northwest (8.6%) and southeast (5.2%), compared with 1.8% in London. In contrast, prevalences of plasmid mediated penicillin resistance and tetracycline resistance showed a more uniform regional distribution. Conclusion: The GRASP data set provides a greater understanding of the epidemiology of both gonococcal infection and antimicrobial resistance. Continued surveillance will ensure prevention and treatment strategies remain responsive to changes in gonococcal epidemiology. [ABSTRACT FROM AUTHOR]