A flat tube cold plate assembly has a channel plate having an opening therethrough defining a flow path. A plurality of flat tubes is retained within the opening in the channel plate along the flow path. A plurality of fins extends within the interior of the flat tube. An upper cover plate and a lower cover plate are fixed over the channel plate with the flat tube disposed therein, for example, by brazing. The flat tube may be readily formed by an extrusion process. The opening in the channel plate may be readily formed by a process such as laser cutting, stamping, or etching.