We present long baseline CO(1-0) mapping of the luminous infrared galaxy NGC 6240 obtained with the IRAM - Plateau de Bure Interferometer. This source is a well known early-stage merging system hosting two active galactic nuclei (AGN). We find a broad CO(1-0) line profile with maximum velocity 800km/s and a total line width of 1400km/s that displays several kinematic components, revealing the complexity of the gas dynamics in this system. We detect a blueshifted CO emission with velocity between -200 and -500 km/s, which peaks around the southern AGN at the same position where the H_2_ outflow is located. We interpret this blueshifted component as an outflow with a mass loss rate of ~500M_{sun}_/yr, originating from the southern nucleus.