An automatic approach to the extraction of change information from time series of multispectral imagery is presented. The method applies the iteratively re-weighted multivarate alteration detection (IR-MAD) algorithm to signal significant changes, recording the results in a georeferenced binary image. A prototype change extraction implemented as an extension to the ENVI/IDL remote sensing data processing user interface, is illustrated using time series of LANDSAT TM and LANDSAT ETM+ multispectral imagery over the center of Novosibirsk.