We present Very Large Array (VLA) observations of H2O and OH (1612 MHz) maser emission toward the protoplanetary nebula OH 231.8+4.2. The H2O observations show two features at V LSR of 23.1 and 44.5 km s−1, coinciding in position within error with the SiO (v=1; J=2−1) maser position from Sánchez Contreras et al. (2000). The H2O and SiO masers are most likely tracing the position of QX Pup, the Mira near the center of OH 231.8+4.2. This position is, however, clearly offset by ∼1 from the axis of the bipolar outflow traced by the OH maser emission. These results suggest the presence of a binary system: one invisible star powering the bipolar outflow and the other, the Mira star QX Pup, associated with the H2O and SiO masers. This scenario requires that the two stars have evolved at very similar rates.