I will present results from the first exposure of a liquid Ar Time Projection Chamber (LArTPC) to a neutrino beam. The data have been collected in 1997 with a 50 liter chamber located between the CHORUS and NOMAD experiments at the CERN West Area Neutrino Facility. I will focus on the analysis of quasi-elastic interactions; despite the limited size of the detector, nuclear effects beyond Fermi motion and Pauli blocking have been observed as perturbations to the pure quasi-elastic kinematics. Applications of the LArTPC technology to long baseline neutrino oscillation experiments will also be discussed.