Considering the general population policies of the Islamic Republic of Iran on life expectancy, health, and disease prevention, this study aims to investigate the pattern of illness and fatality rate in different geographical areas of Iran. It analyzes the climate of 31 provinces in Iran and studies five types of diseases with the highest fatality rate. The findings can sketch out a fatality map to guide policy makers for the prevention and control of diseases. The research method is descriptive-analytical primarily, and cross-sectional secondarily. There are two types of data: causes of death extracted from National Organization of Civil Registration, and demographic and climate data from the National Statistics of Iran from 2006 to 2016. The data were fed into Excel and GIS programs for analysis. The findings show that the first five causes of death in Iran are: cardiovascular (54%), unknown symptoms (17%), cancers (14%), respiratory (11%), and infectious-parasitic (4%) which indicate 70% of the current fatalities. In the past 10 years, cardiovascular diseases, cancers, and respiratory illnesses have increased 3. 3, 2. 3, and 1. 05 percent, respectively, and the diseases with unknown symptoms and infectious-parasitic diseases have decreased 6. 8 and 2. 02 percent, respectively. Also, the study showed that there is a sinuous pattern applicable to fatality in difference seasons, peaking particularly in autumn and winter (November, December, and January).