OBJECTIVE: To evaluate the success of treatment with periurethral collagen injections in patients suffering from stress urinary incontinence (SUI) with bladder neck hypermobility and intrinsic sphincter deficiency MATERIALS AND METHODS: Forty women suffering from (SUI) were selected and divided into GI (consisting of 13 women with SUI and bladder neck hypermobility) and GII (consisting of 27 women with SUI and intrinsic sphincter deficiency). Periurethral collagen was injected followed by a subjective evaluation (the need for urinary protectors) and an objective evaluation through urodynamic study before and after the treatment RESULTS: It was noticed that after 9 months there was a decrease in the need of urinary protectors in the two groups. It was observed through the urodynamic study that either cure or improvement was achieved in 46% in GI and 40.7% in GII. There was a significant increase in the leak pressure in GII. Moreover, there was a decrease in the volume of urine leak in the two groups, being the results in GII statistically significant CONCLUSIONS: It was concluded that the periurethral collagen injection is useful for the treatment of the SUI. The results in hypermobility are similar to those in intrinsic sphincter deficiency. In fact, it is a very simple out patient's procedure, with little side effects.