  We have used the Wide Field and Planetary Camera 2 on board the Hubble Space
Telescope to obtain V and I images of seven nearby galaxies. For each, we have
measured a distance using the tip of the red giant branch (TRGB) method. By
comparing the TRGB distances to published Cepheid distances, we investigate the
metallicity dependence of the Cepheid period-luminosity relation. Our sample is
supplemented by 10 additional galaxies for which both TRGB and Cepheid
distances are available in the literature, thus providing a uniform coverage in
Cepheid abundances between 1/20 and 2 (O/H)solar. We find that the difference
between Cepheid and TRGB distances decreases monotonically with increasing
Cepheid abundance, consistent with a mean metallicity dependence of the Cepheid
distance moduli of (delta(m-M))/(delta[O/H]) = -0.24 +- 0.05 mag/dex.
