The Confocal and Specialized Microscopy Shared Resource is a fully Cancer Center-managed facility. Subcellular imaging is an essential tool in cancer biology. However, although the ideal specimen for conventional optical microscopy is two-dimensional, biological material is organized in three dimensions. Several technologies, notably confocal microscopy, are available to collect 3D images of biological samples, with a spatial resolution superior to conventional microscopy. These essential imaging systems are expensive and difficult for inexperienced users to operate and maintain, and are not routinely available in individual research laboratory. The services provided by the Confocal and Specialized Microscopy Shared Resource are: one-photon laser scanning confocal microscopy multiphoton excitation confocal microscopy spinning-disk confocal microscopy digital deconvolution microscopy All of these 3-dimensional fluorescence imaging technologies are made conveniently and affordably available to HICCC members and other Columbia University researchers in a centralized facility, with training, assisted use, and consultation on data analysis and presentation provided by a full-time employee and a manager. Since 1996, the facility has been used by more than 154 principal investigators from over 30 basic science and clinical departments at Columbia University, and has contributed images for more 200 publications. The facility is currently used at 75% of its maximal capacity during peak hours. In January 2007, the facility moved into newly renovated space in the Irving Cancer Research Center. The facility continually seeks to add new imaging technologies to meet the scientific needs of our users. In conjunction with the HICCC, we will introduce a new confocal microscope in the next year. During the last period of the CCSG, 37% of the users have been Cancer Center members with peerreviewed funding, with those members representing 26% of the hours used in the facilty. The total operating budget of the facility is $273,025, of which we are requesting $79,749 from the CCSG.