Objective To investigate the association between temperature and daily mortality in Shanghaifrom June 1, 2000 to December 31, 2001. Methods Time-series approach was used to estimatethe effect of temperature on daily total and cause-specific mortality. We fitted generalized additivePoisson regression using non-parametric smooth functions to control for long-term time trend, seasonand other variables. We also controlled for day of the week. Results A gently sloping V-likerelationship between total mortality and temperature was found, with an optimum temperature (e.g.temperature with lowest mortality risk) value of 26.7,℃ in Shanghai. For temperatures above theoptimum value, total mortality increased by 0.73% for each degree Celsius increase; while fortemperature below the optimum value, total mortality decreased by 1.21% for each degree Celsiusincrease. Conclusions Our findings indicate that temperature has an effect on daily mortality inShanghai, and the time-series approach is a useful tool for studying the temperature-mortalityassociation.