Since 1974, >100 different surveys have been carried out throughout the developing world to estimate the prevalence of lameness due to poliomyelitis. Reported prevalence rates have ranged from <1 to a high of 25 per 1,000 children surveyed and have prompted many countries to undertake polio vaccination programs. A review of surveys conducted to date reveals considerable variation in both the choice and use of survey methods and in the assumptions made in the analysis and interpretation of findings. More precise and comparable data about the risk of poliomyelitis could be obtained in future surveys by incorporating a standard case definition, by using house-to-house case-finding methods in representative community-based samples, by analyzing and presenting rates in more clearly defined ways, and by selecting stable populations for study.