This review discusses optical observations of flares and the results gleaned from these. Excellent reviews of flare activity have been published in the past and one might mention in particular Kunkel (1975), Gershberg (1978) and Gurzadyan (1980). In general these have been more broadly based than the present review incorporating other aspects of flare stars e.g. BY Dra variability, spectroscopic observations, etc. Since these other aspects of flare star behaviour are being covered elsewhere in this volume we will confine ourselves exclusively to optical photometry of the flare phenomenon itself. We will also confine ourselves to the solar-neighbourhood flare stars (i.e. the UV Ceti stars) since other contributors will discuss the T-Taurl, RS CVn, BY Dra and other flaring objects.