Understanding the nature and consequences of intellectual and developmental disabilities is challenging, especially when the condition is rare, affected individuals are geographically dispersed, and/or resource constraints limit large-scale studies involving direct assessment. Surveys provide an alternative methodology for gathering information but must be carefully designed and interpreted in light of obvious limitations. In this paper we discuss the potential of surveys in understanding a disabling condition; delineate characteristics of successful survey research; describe a survey of families of individuals with fragile X syndrome; and synthesize major findings. The survey has provided new information about the nature and consequences of fragile X syndrome in a cost-effective fashion, suggesting that survey methodology has a useful place in creating new knowledge about intellectual and developmental disabilities.