Objective The objective of this article is to determine whether cutaneous allodynia (CA) influences the response to treatment with occipital transcutaneous electrical stimulation (OTES) in chronic migraine (CM) and chronic tension-type headache (CTTH). Methods One hundred and sixty consecutive patients with CM or CTTH were randomized to be treated with real or sham OTES stimulation three times a day for two consecutive weeks. All patients completed the validated 12-item allodynia symptom checklist for assessing the presence and the severity of CA during headache attack. Primary end-point was change (≥50%) in number of monthly headache-free days. Results There was a significant difference in the percentage of responders in the real OTES compared with sham OTES group ( p <0.001). Importantly, there was not a significant change of monthly headache-free days in the allodynic patients with CM and CTTH treated both with real and sham OTES, while the number of headache-free days per month was significantly reduced in the real (86%) but not in the sham group (7%) of non-allodynic patients with CTTH and CM. Conclusions Severe CA is associated with decreased response to treatment with OTES in patients with CM and CTTH.