The effect of series resistance on the apparent semiconductor junction capacitance C' has been studied after Goodman [J. Appl. Phys. 34, 329 (1963)] in an attempt to explain the occurrence of minima in the apparent C' -2 vs voltage characteristics at high frequencies and for a large series resistance. A correction scheme has been formulated to convert C'-2 into the actual C-2 at any bias and frequency. The present model is consistent with the apparent capacitance behavior of a commercial Si Zener diode in series with a discrete resistor.