PURPOSE: To evaluate the clinical and urodynamic significance of the beaking sign at cystography in patients with stress urinary incontinence (SUI). MATERIALS AND METHODS: We retrospectively reviewed the cystograms of 253 patients with SUI, defining the beaking sign as the triangular contrast collection below the bladder base in the resting state without overt leakage. Various clinical parameters including patient age, symptom duration, parity, the one-hour pad test, and urodynamic study data including Valsalva leak point pressure (VLPP) and maximal urethral closing pressure (MUCP) were compared between the beaking-positive and the beaking-negative group. The distribution of Blaivas type in SUI between these two groups was also analysed. RESULTS: The beaking sign was observed in 153 patients (60%). Those who were older and showed greater parity more often belonged to the beaking-positive group than the beaking-negative (p<0.05). Both VLPP and MUCP were significantly lower in the beaking-positive group than in beaking-negative group (p=0.03; p=0.01, respectively). Type-0 or -I SUI was more common in the beaking-negative group, while the frequency of other types was similar between the two groups. CONCLUSION: The beaking sign has clinical and urodynamic significance, reflecting functional deficiencies of the intrinsic sphincter, and may possibly be regarded as an additional parameter in the planning of treatment.