We retrospectively identified 37 cases in which urinary incontinence occurred at rest during urodynamic testing in the absence of a coincident detrusor contraction or urethral relaxation. This phenomenon, genuine stress incontinence at rest, was observed during 9.6% of multichannel cystometrograms performed at our institution. The observed urine loss occurred at bladder volumes between 145 ml and 800 ml. Loss occurred with bladder overdistension (overflow incontinence) in only 3 subjects (8%). Decreased bladder compliance was observed in 11 (30%) and decreased outlet resistance was demonstrated in 24 (65%). Our findings suggest that genuine stress incontinence at rest is relatively common in a referred population of incontinent women. This phenomenon is associated with impaired urethral function and/or decreased bladder compliance.