Objective To investigate the effectiveness of botulinum toxin A (BTX-A) injection to the external urethral sphincter guided by ultrasound in the treatment of various types of lower urinary tract dysfunction.Methods Twenty-two patients with urinary retention caused by neurological dysfunction (neurogenic bladder) were recruited,of which 18 were men and 4 women.They had various types of lower urinary tract dysfunction including detrusor external sphincter dyssynergia (DESD) in 7,nonrelaxing urethral sphincters in 5,and detrusor underactivity in 10.BTX-A (100 U) was injected into the external urethral sphincter at three different points guided by ultrasound.Clinical effects and urodynamic parameters were compared at baseline and after treatment.Results After treatment the urinary function and urodynamic parameters in each group improved significantly compared with the baseline.Maximum efficacy was observed at the 4th week.In the DESD group,3 patients (43％) had an excellent result and 3 (43％) had significant improvement; in the nonrelaxing sphincter group 3 (60％) had excellent results and 2 (40％) showed significant improvement; in the detrusor underactivity group 5 (50％) had excellent results and 3 (30％) had significant improvement.There were no obvious side effects.Conclusions BTX-A injections guided by ultrasound can accurately locate the external urethral sphincter.It is a simple and repeatable method for the treatment of lower urinary tract dysfunction.