  We describe the use of pulsars to study small-scale neutral structure in the
interstellar medium (ISM). Because pulsars are high velocity objects, the
pulsar-Earth line of sight sweeps rapidly across the ISM. Multiepoch
measurements of pulsar interstellar spectral line spectra therefore probe ISM
structures on AU scales. We review pulsar measurements of small scale structure
in HI and OH and compare these results with those obtained through other
techniques.
