Abstract
NGC 4258 is a key galaxy for the absolute calibration of the Extragalactic Distance Scale, given the extremely precise (3%) distance that has been obtained through observations of water masers orbiting the central black hole. I will present the results of a survey for Cepheids in this galaxy, carried out using ACS and NICMOS on HST, and will discuss its implications for cosmology and the distance to the Large Magellanic Cloud.