The mid-infrared spectrum of the Cl-37(-)-H-2 anion complex has been measured over the 3990-4050 cm(-1) range (H-H stretch region) using infrared vibrational predissociation spectroscopy. The spectrum features a well resolved Sigma-Sigma transition red shifted by 156 cm(-1) from the free H-2 molecule stretch. Analysis of the P and R branch line positions using a linear molecule energy level expression yields nu (0)=4004.77 +/-0.08 cm(-1), B"=0.853 +/-0.002 cm(-1), D"=(9.3 +/-1.0)x10(-5)cm(-1), B"=0.919 +/-0.002 cm(-1), and D"=(9.0 +/-1.0)x10(-5) cm(-1). The Cl--H-2 complex appears to have a linear equilibrium structure, with a vibrationally averaged separation of 3.19 Angstrom between the Cl- and the H-2 center-of-mass. Vibrational excitation of the H-H stretch induces a 0.12 A contraction in the intermolecular bond.