We present a comparative study between headache clinic populations from 2 inherently different regions of the United States. Using standardized methods, 1 of us (JFR) prospectively evaluated 578 new patients attending the headache clinic at the University of California in San Diego. In a similar manner, we subsequently evaluated 115 new patients presenting to the headache clinic at the University of South Alabama in Mobile, Alabama. We found few differences between the 2 populations. These differences more Likely reflect regional variations in healthcare delivery or methodologic artifact than intrinsic dissimilarities.