Background: Urinary incontinence is common in women. Because treatments differ, urge incontinence should be distinguished from stress incontinence. To make this distinction, current guidelines recommend an extensive evaluation that is too time-consuming for primary care practice. Objective: To test the accuracy of a simple questionnaire to categorize type of urinary incontinence in women. Design: Multicenter, prospective study of the accuracy of the 3 Incontinence Questions (3IQ) compared with an extended evaluation to distinguish between urge incontinence and stress incontinence. Setting: 5 academic medical centers in the United States. Participants: 301 women enrolled from April to December 2004 who were older than 40 years of age (mean age, 56 years [SD, 11]) with untreated incontinence for an average of 7 years (SD, 7) and a broad range of incontinence severity. Measurements: All participants included in the analyses answered the 3IQ questionnaire, and a urologist or urogynecologist who was blinded to the responses performed the extended evaluation. Sensitivity, specificity, and likelihood ratios were determined for the 3IQ. Results: For classification of urge incontinence and with the extended evaluation as the gold standard, the 3IQ had a sensitivity of 0.75 (95% CI, 0.68 to 0.81), a specificity of 0.77 (CI, 0.69 to 0.84), and a positive likelihood ratio of 3.29 (CI, 2.39 to 4.51). For classification of stress incontinence, the sensitivity was 0.86 (CI, 0.79 to 0.90), the specificity was 0.60 (CI, 0.51 to 0.68), and the positive likelihood ratio was 2.13 (CI, 1.71 to 2.66). Limitations: Participants were enrolled by urologists and urogynecologists at academic medical centers. Conclusions: The 3IQ questionnaire is a simple, quick, and non-invasive test with acceptable accuracy for classifying urge and stress incontinence and may be appropriate for use in primary care settings. Similar studies are needed in other populations. We also need a clinical trial comparing the outcomes of treatments based on the 3IQ and the extended evaluation. © 2006 American College of Physicians.