The etiology of BOO is diverse and definitely gender specific. Often anatomic causes induce functional abnormality that remains somewhat unique for each individual, regardless of sex. A full appreciation of the possible etiologies of obstruction is necessary in order to identify overt and more subtle scenarios. In women, iatrogenic causes of obstruction are the most common. Other entities account for far fewer of the cases. The obstruction evaluation in women is somewhat more diverse in terms of modalities used, with no single grouping of techniques that are generally apropos. Individualized evaluation remains a tenet of analysis, and urodynamic criteria used to diagnose BOO in women continue to evolve.