This study examines the residential demand for electricity by time-of-use in Switzerland. For this purpose, an almost ideal demand system (AIDS) model for peak and off-peak electricity consumption is estimated using panel data covering the years 1987 to 1990 and 21 cities. The empirical analysis characterizes the Swiss residential electricity market as rather price responsive. The own partial price elasticities are estimated to range between -1.29 and -1.50 during the peak period and between -2.36 and -2.42 during the off-peak period. These elasticities show a high responsiveness of electricity consumption to changes in peak and off-peak prices. Moreover, the positive values of the partial cross price elasticities and substitution elasticities show that peak and off peak electricity are substitutes.