New performance-based earthquake engineering methods developed by the Pacific Earthquake Engineering Research Center, the Applied Technology Council, and others include damage analysis at a highly detailed level, requiring the compilation of fragility functions for a large number of damageable generic structural and nonstructural components. This brief paper presents the development of a fragility function for hydraulic elevators. It uses post-earthquake survey data from 91 elevators in nine California locations after two earthquakes. Surveys were used to collect data on facilities and elevators. Ground-motion records from the California Integrated Seismic Network were used to estimate engineering demands at each site. Binary regression analysis was used to fit a fragility function, which takes the form of a lognormal cumulative distribution function with median value of PGA=0.42 g and logarithmic standard deviation of 0.3. The fragility function appears to be reasonable based on four criteria.