Urethral injection is a convenient, minimally invasive means of treating stress urinary incontinence (SUI). We present long-term follow-up data from 20 patients originally recruited in 1994-95 (mean age 67 years) to receive urethral injection with dextranomer/hyaluronic acid (Dx/HA) copolymer. The majority of patients had failed previous therapy for SUI. If the first injection was unsuccessful, up to two further injections were offered. Only 3 patients (15%) failed to show a response to treatment. Sixteen women were reassessed during 2001 (4 had died of causes unrelated to the study treatment). A sustained response throughout the follow-up period was reported in 9/16 patients (57%), with incontinence recurring in just 4 (25%). None of the 7 patients with persistent or recurrent incontinence were cured by subsequent treatments, including surgery. In conclusion, urethral injection with Dx/HA copolymer offers promising long-term efficacy in the treatment of SUI, regardless of old age or failure to respond to previous therapy.