Cases of consecutive new patients seen at orthopedic spine and shoulder clinics were reviewed. Four percent of spine patients had significant shoulder pathology, and 3.6% of shoulder patients had significant spine pathology. Identification of the correct pain generator is a prerequisite for effective treatment in patients with neck and/or shoulder problems. However, distinguishing between the two can be difficult. Relative frequencies of how often one is mistaken for the other have not been well established. Six hundred ninety-four new patients were seen at the orthopedic shoulder clinic (n = 452) or spine clinic (n = 242) at an academic institution during a 2-year period. One hundred seven patients had previous shoulder surgery, and 39 had previous neck surgery. The 548 patients (shoulder clinic, 345; spine clinic, 203) who had no previous surgery were reviewed with respect to workup performed, final diagnosis, subsequent operative procedures, and incidence of referral from the shoulder clinic to the spine clinic and vice versa. Among the patients seen at the shoulder clinic, 325 (94.2%) had shoulder pathology, 6 (1.7%) had neck but no shoulder pathology, 6 (1.7%) had shoulder and neck pathology, and 8 (2.3%) had an unidentifiable cause of pain. Of the 12 patients with neck pathology, none underwent neck surgery. Among the patients seen at the spine clinic, 182 (89.7%) had neck pathology, 5 (2.5%) had shoulder but no neck pathology, 3 (1.5%) had neck and shoulder pathology, and 13 (6.4%) had an unidentifiable cause of pain. Of the 8 patients with shoulder pathology, 1 (12.5%) underwent shoulder surgery. Our analysis suggests that for patients who present to a shoulder surgeon's clinic for shoulder pain, 3.6% will turn out to have neck pathology. For patients who present to a spine surgeon's clinic for neck pain, 4% may turn out to have shoulder pathology. Thus, approximately 1 in 25 patients seen at a surgeon's clinic for a presumed shoulder or neck problem may exhibit neck-shoulder crossover, in which pathology in one may be mistaken for or coexist with the other.