Aim of the study was to evaluate the efficacy of tolterodine in relation to different urodynamic findings of detrusor overactivity (DO). Women with urodynamic diagnosis of DO were prospectively included into two groups: with involuntary detrusor contractions during the cystometric filling phase (group 1) or after provocative manoeuvres (group 2). Tolterodine 4 mg ER was prescribed to all women. Drug efficacy was assessed using a 3-point scale. Women were defined responders if they were improved/cured after 3 months of therapy, and non-responders if symptoms did not change. The outcome of therapy was compared between groups. A total of 111 women were included. The groups did not differ for demographic characteristics. After 12 weeks, we found a significant difference (P = 0.0008) between groups in terms of tolterodine efficacy with a better response rate in group 1. Our study shows that tolterodine efficacy may be related to different urodynamic findings of DO.