To evaluate the efficacy of baclofen in combination with antimuscarinics to treat women with an overactive bladder (OAB) with abnormal voiding patterns. An action research and chart review was conducted in 245 OAB women. Women were prescribed tolterodine or oxybutynin with or without baclofen after urodynamics. The complaint of voiding difficulty was followed up one week later. There was a significant difference in the occurrence of voiding difficulty after antimuscarinic administration in OAB women with abnormal voiding patterns compared with normal patterns (18% vs 4.9%, respectively; p = 0.013). The clinical difference of voiding difficulty after treating with antimuscarinics between both voiding patterns disappeared after adding baclofen (abnormal voiding pattern vs normal pattern; 11.1% vs. 5.6%, respectively; p = 1.000). Combined use of baclofen and antimuscarinic agents could reduce voiding difficulty in treating women with overactive bladders with abnormal voiding patterns.