en Original Article <p dir="ltr" style="text-align: justify;"><span style="font-family: times new roman;"><strong>Background:</strong> The role of temperature changes, as an environmental risk factor, in the human health status has been investigated in recent studies. Accordingly, the present two-year study was conducted to evaluate the incidence of myocardial infarction (MI) in warm and cold seasons in Ali-ibn Abi Talib Hospital, Rafsanjan, Iran.</span></p> <p dir="ltr" style="text-align: justify;"><span style="font-family: times new roman;"><strong>Materials and Methods:</strong> In this descriptive and cross-sectional study, 264 patients hospitalized with MI during a two-year period (2013-2014) were included. Data on the participants were obtained from their electronic medical files and on the weather from the official Rafsanjan Weather Bureau station. The collected data was then analyzed using statistical tests including chi-squared test, Fisher&#39;s exact test, and logistic regression model in SPSS software.</span></p> <p dir="ltr" style="text-align: justify;"><span style="font-family: times new roman;"><strong>Results:</strong> Data showed that 41.80% of MI occurred in hot weather, 14% in cold, and the remaining 37.12% in mild weather. According to the type of MI, 49.47% of non-ST elevation myocardial infarction (NSTEMI) and 44.44% of ST-segment elevation myocardial infarction (STEMI) occurred in very hot weather while 13.54% of NSTEMI and 18% of STEMI occurred in very cold weather. This difference was not significant.</span></p> <p dir="ltr" style="text-align: justify;"><span style="font-family: times new roman;"><strong>Conclusions:</strong> Based on our data, MI had occurred mostly in hot weather and more than half of the cases were NSTEMI.</span></p> Temperature, Heart Attack, Myocardial Infarction 160 165 http://johe.rums.ac.ir/browse.php?a_code=A-10-136-1&slc_lang=en&sid=1 A Esmaeili Nadimi dr_esmaeili_n@yahoo.com 2240031947532846003928 2240031947532846003928 Yes Dept. of Cardiology, School of Medicine, Rafsanjan University of Medical Sciences, Rafsanjan, Iran. Rafsanjan University of Medical Sciences M Hasani mahsima_h@yahoo.com 2240031947532846003929 2240031947532846003929 No General Physician, Rafsanjan University of Medical Sciences, Rafsanjan, Iran. Rafsanjan University of Medical Sciences M Allahtavakoli mohammadatir@yahoo.com 2240031947532846003930 2240031947532846003930 No Dept of. Physiology, Physiology -Pharmacology Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran Rafsanjan University of Medical Sciences E Hakimizadeh hakimizadeh_elham@yahoo.com 2240031947532846003931 2240031947532846003931 No Physiology-Pharmacology Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran. Rafsanjan University of Medical Sciences H Bakhshi 2240031947532846003932 2240031947532846003932 No Molecular-Medicine Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran Rafsanjan University of Medical Sciences