The flow and heat transfer characteristics of a pair of embedded counter-rotating vortices are studied experimentally. In order to control the strength of longitudinal vortices, angle of attack of the vortex generators is varied from +/-20degrees to +/-45degrees, and the spacing between the vortex generators is 4 cm apart. The heat transfer measurements using thermo-chromatic liquid crystal are made to provide the local surface distributions of heat transfer coefficients. The following conclusions are obtained from the present experiment. For the common-flow-down cases, two maximum values in the local heat transfer distributions exist for the three angles of attack. With the common-flow-up cases, only one maximum value exists. The common-flow-down cases show better heat transfer characteristics than the common-flow-up cases.