  Pulsational variability is observed in several types of main sequence stars
with anomalous chemical abundances. In this contribution I summarize the
relationship between pulsations and chemical peculiarities, giving special
emphasis to rapid oscillations in magnetic Ap stars. These magneto-acoustic
pulsators provide unique opportunities to study the interaction of pulsations,
chemical inhomogeneities, and strong magnetic fields. Time-series monitoring of
rapidly oscillating Ap stars using high-resolution spectrometers at large
telescopes and ultra-precise space photometry has led to a number of important
breakthroughs in our understanding of these interesting objects. Interpretation
of the roAp frequency spectra has allowed constraining fundamental stellar
parameters and probing poorly known properties of the stellar interiors. At the
same time, investigation of the pulsational wave propagation in chemically
stratified atmospheres of roAp stars has been used as a novel asteroseismic
tool to study pulsations as a function of atmospheric height and to map in
detail the horizontal structure of the magnetically-distorted p-modes.
