  We present an analysis of the RZ Cassiopeia O-C diagram for a 30-year period,
based on data published by the AAVSO. The new parabolic light-elements are
determined and P-dot was estimated. This enabled us to establish the value of
M-dot, the rate of the mass transfer between components of this eclipsing
binary. Deviations from the parabola in the RZ Cas O-C diagram have a wavelike
trend. The pulsation of the primary component influences the scatter of O-C
points, as well as it influences the shape of the eclipse. Some physical points
on such O-C behavior are presented.
