OBJECTIVE AND INTRODUCTION: Cowper's syringocele is a cystic dilation of the bulbourethral gland duct, initially defined by Maizels et al. in 1983. Although obstructive and non-obstructive types of this rare anomaly are described, clinical symptoms are highly unspecific. Therefore, we report 12 cases of children and young adults diagnosed with Cowper's syringocele to further clarify clinical course, comorbidity and treatment strategies. STUDY DESIGN: We retrospectively collected clinical data of 12 children and young adults from birth to 18.5 years (median 7.2 years) who had been treated in four different institutes during a period of 16 years. The primary specific diagnostic work-up consisted of ultrasound, cystourethrography, and cystoscopy. RESULTS: 3Older patients with a median age of 11.8 years clinically presented with obstructive voiding pattern or gross hematuria; infants with a median age of 0.6 years presented with febrile urinary tract infections (UTIs). After cystoscopic confirmation in all patients, endoscopic treatment was possible in nine; open surgical resection was necessary in three patients. Because of intrauterine megacystis and chronic renal failure, one boy underwent suprapubic diversion with a cystostomy soon after birth. Owing to urological comorbidity or later complications, additional procedures were necessary, for example, resection of minor urethral valves, prophylactic circumcision for UTI, endoscopic or open antireflux procedures, and occasionally complex bladder reconstructions in the long term. DISCUSSION: According to our data, the initial clinical symptoms of Cowper's syringocele were related to presenting age rather than the previously described type of syringocele according to Maizels et al. Infants presented with febrile UTIs; however, older boys and young adults had mainly voiding problems or nocturnal enuresis. Therefore, the clinical significance of the described syringocele types must be questioned. Eighty-three percent of our patients showed additional urological pathology such as vesicoureterorenal reflux, ureteropelvic junction obstruction, megaureter, or minor urethral valves. Thus, Cowper's syringocele hardly seems to be an isolated pathology. CONCLUSION: Although rare, Cowper's syringoceles should be considered in differential diagnosis of infravesical obstruction in boys and young adults. Diagnostics are usually justified by presenting symptoms such as UTI or urinary flow impairment, which seem to be age dependent. Despite modern diagnostic tools, diagnosis is usually made by cystourethrography and sometimes accidentally by cystoscopy. Considerable urological comorbidities and consecutive bladder dysfunction need long-term follow-up.