Existing and planned experimental work in several NIDCD ROI-funded laboratories requires sophlsficated measures of auditory function in small mammals. The breadth of these auditory funcfion measures ranges from simple high-throughput screening up to full comprehensive, frequency-specific measures concerning the middle ear, outer hair cell funcfion, and neural funcfion. These measures can be tailored for simple screening to frequency-specific threshold estimates. Measures of middle ear function will be added. The Core Auditory Function facility will ensure that these complex auditory measures are performed efficiently and accurately with the appropriate apparatus, under standardized, and calibrated condifions, and managed with a comprehensive database that stores, manages and retrieves individual and aggregate experimental auditory data. The Auditory Function Core consists of a Central Auditory Laboratory, three individual auditory measurement facilities, and a noise damaging facility, all in close proximity. The facilifies have convenfional apparatus and many custom components including high-frequency transducers for specific species. Roufine measures include distortion product otoacousfic emissions and frequency-specific auditory measures at the level ofthe brainstem tailored to the specific small mammals being measured, currently mice and guinea pigs. The three measurement stafions include sound and electrically shielded rooms, and specialized systems (Tucker Davis Technologies, Intelligent Hearing Systems) that include passive attenuators, filters, signal averaging algorithms, stimulus creation, etc. A fourth station will be used for generafing and controlling acousfic signals that are used for experimentally-controlled auditory damage. Our approach is to develop consistent, redundant, modular systems that provide all of these measures or subsets of these measures in a standardized, well-characterized manner;to plan for equipment and personnel redundancy so that no experiment would ever be compromised in the face ofthe usual transient breakdowns;and to develop a comprehensive server-based database so that every scientist can locate and download any result at any fime using a consistent interface.