OBJECTIVE: This pilot study reports the findings of a randomized controlled trial (RCT) investigating the feasibility, tolerability, acceptability, and initial estimates of efficacy of mindfulness-based cognitive therapy (MBCT) compared to a delayed treatment (DT) control for headache pain. It was hypothesized that MBCT would be a viable treatment approach and that compared to DT, would elicit significant improvement in primary headache pain-related outcomes and secondary cognitive-related outcomes. MATERIALS AND METHODS: RCT methodology was employed and multivariate analysis of variance models were conducted on daily headache diary data and preassessment and postassessment data for the intent-to-treat sample (N=36), and on the completer sample (N=24). RESULTS: Patient flow data and standardized measures found MBCT for headache pain to be feasible, tolerable, and acceptable to participants. Intent-to-treat analyses showed that compared to DT, MBCT patients reported significantly greater improvement in self-efficacy (P=0.02, d=0.82) and pain acceptance (P=0.02, d=0.82). Results of the completer analyses produced a similar pattern of findings; additionally, compared to DT, MBCT completers reported significantly improved pain interference (P<0.01, d=-1.29) and pain catastrophizing (P=0.03, d=-0.94). Change in daily headache diary outcomes was not significantly different between groups (P's>0.05, d's≤-0.24). DISCUSSION: This study empirically examined MBCT for the treatment of headache pain. Results indicated that MBCT is a feasible, tolerable, acceptable, and potentially efficacious intervention for patients with headache pain. This study provides a research base for future RCTs comparing MBCT to attention control, and future comparative effectiveness studies of MBCT and cognitive-behavioral therapy.