Objective: To determine the proportion of symptomatic patients attending public sexually transmitted disease (STD) clinics who fail to seek care within 7 days of the onset of STD symptoms and their self-reported reasons for delays in obtaining care. Design: Interviewers administered 23-item questionnaire to a cross section of STD clinic clients between April and September 1995. Setting: Five urban STD clinics in the United States (Birmingham, AL; St Paul, MN; San Francisco CA; Seattle, WA; and Raleigh, NC). Results: Of 1,621 patients with genitourinary symptoms, over one third (35% of men, 37% of women) presented to STD clinics only after 1 week or moro of symptoms. Men with genital warts (73%) or with non gonococcal urethritis (23.1%) or symptomatic men who were recent contacts to sex partners with STDs were significantly more likely to delay clinic attendance more than a week than men with gonorrhea (6.5%, p < 0.001 for each). Overall 43.8% of women receiving specific clinical diagnoses other than genital warts delayed clinic attendance for more than 1 week. When asked why they delayed clinic attendance, respondents were most likely to respond that they had hoped their symptoms would 'go away' (48.5% of men and 49.4% of women who waited a week or more before seeking care). Conclusion: A substantial proportion of patients with genitourinary symptoms attending public STD clinics delay seeking care for a week or moro, increasing their likelihood of complications and of transmission of infection to others. Interventions to promote more timely clinic attendance may help reduce STD morbidity in the United States.