This paper focuses on the effect of the rack inlet temperatures resulting from chilled air exhausting from perforated tiles situated in both the hot and cold aisles of a raised floor data center. Only the above floor (raised floor) flow and temperature distributions were analyzed for various flowrates exhausting from the perforated tiles. A Computational Fluid Dynamic(CFD) model was generated for the room with electronic equipment installed on a raised floor with particular focus on the effects on rack inlet temperatures of equipment heat load, placement of air conditioning (A/C) units and chilled air flowrates. Forty racks of data processing (DP) equipment were arranged in rows in a data center cooled by chilled air exhausting from perforated floor tiles. The chilled air was provided by four A/C units placed inside a room 12.1 m wide x 13.4 m long. Since the arrangement of the racks in the data center was symmetric only one-half of the data center needed to be modeled. The numerical modeling was performed using a commercially available finite control volume computer code called Flotherm (Trademark of Flomerics, Inc.). The flow was modeled using the k-e turbulence model. Results are displayed to provide some guidance on the design and layout of a data center.