We aimed to evaluate the efficacy and safety of combination treatment using anticholinergics with α-blocker for initial treatment of both overactive bladder (OAB) and other lower urinary tract symptoms (LUTS), secondary to BPH. A 12-week, randomized, double-blind, placebo-controlled trial was conducted at four urology clinics in Korea, involving men, aged 50 years or older, with LUTS related to BPH and OAB. A total of 176 patients were randomly assigned to receive doxazosin (4 mg) plus placebo or doxazosin (4 mg) plus tolterodine SR (4 mg), once a day for 12 weeks. Changes from baseline in total International Prostate Symptom Score (IPSS), bladder diary variables, patient perception of bladder condition (PPBC), uroflowmetry, postvoid residual volume and IPSS subscores (voiding and storage) were analyzed. Of the 176 enrolled patients, 91 had doxazosin gastrointestinal therapeutic system (GITS) and placebo, and 85 had combined medication with doxazosin GITS and tolterodine SR. Compared with the doxazosin plus placebo group, the doxazosin plus tolterodine group showed significant reductions in IPSS storage subscore and improvement in the quality of life item, urgency episodes, as well as in micturition frequency at weeks 4 and 12. However, it failed to improve PPBC at week 4 as well as at week 12. Earlier intervention with anticholinergics plus α-blocker was tolerated well, including the questions about urinary retention (n=1) and dry mouth (n=2). Initial combination treatment of anticholinergics plus α-blocker showed positive results for men with LUTS related to BPH and OAB symptoms and did not increase the risk of urinary retention.