Background:In the past three decades, Tehran, capital of Iran, has experienced warmer summers so we need to determine heat-related mortality to establish appropriate public health activities during hot summersThe aim of this study was to detect heat waves during the last decades and then determine excess mortality in immediate and lagged times.Methods: An ecological study based on time-series model was conducted in Tehran for re- cent decade using generalized linear lagged model (GLLM) with Poisson regression in 2001- 2011Maximum daily temperature was heat exposure for death outcome on the same day (lag 0), 3 (lag 01) and also 7 (lag 02) day moving averageRelative risk with 95% confidence was reported to quantify for increasing of daily mortalities for 1¡C risen exposureAir pollu- tants considered as confounders in final modelResults: Total excess mortality during 17 heat waves was 1069 (8.9 deaths/Heat wave days)All non-external cause of death increased significantly during heat waves (3%-9%) with (RREuro Surveillance (Bulletin Europeen Sur Les Maladies Transmissibles; European Communicable Disease Bulletin) 1.03, 95% CI: 1.01, 1.05 and RREuro Surveillance (Bulletin Europeen Sur Les Maladies Transmissibles; European Communicable Disease Bulletin)1.09, 95% CI: 1.07, 1.09) and after adjusting for ozone and PM10 raisedCause-specific deaths (especially circulatory disease) and death among elderly increased during heat waves (especially in the hottest wave)The largest posi- tive lagged effect of hot temperature although seen during hottest waves for all mortalitiesThree waves had the most harvest effect for all categories of mortalitiesConclusion: This study showed excess mortalities resulted from hot temperatures and exac- erbated with air pollutants in Tehran in the context of climate changeForward displacement mortality and lagged mortalities were seen, but our results were not conclusive about the displacement pattern of mortalities.