The high-range estimate of 1.3% by the National Arthritis Data Workgroup for the prevalence of the entire spectrum of spondyloarthropathies (SpAs) suggests that SpAs may be more prevalent than rheumatoid arthritis (RA) in the United States. Recent surveys from many European countries using the same sample population have also found SpA to be at least as common as RA in most of the studied populations, including Finnish, Swedish, Lithuanian, French, Italian, and Turkish. Among Asian populations, China has the highest prevalence of SpA, with reported estimates generally higher than that of RA. In Thailand and Vietnam, the two diseases are probably equally common, whereas RA seems to be more prevalent than SpA in the rest of Asia, the Pacific Region, and Latin America, as indicated by studies following the COPCORD (Community-Oriented Program for the Control of Rheumatic Diseases) protocol. Both rheumatic disorders are rare in Africa, but SpA is less common than RA.