The monitoring of the Earth’s surface temperature shows an increase of about 0.6 °C since 1860. Climatologists relate this increase to climate change specifically temperature variability during the past 50 years. Therefore, temperature has been used as a key climatic element for studying climate change worldwide. Scientists believe that any significant trend in temperature could be a sign of climate change. Thus, in this research, temperature has been used to study climate change of the west of Iran. Nineteen synoptic stations located in six province of west of Iran including Hamedan, Ilam, Kermanshah, Kurdistan, Western Azarbaijan, and Zanjan were selected for temperature detection of trend. After accuracy and homogeneity tests, temperature data were analyzed by parametric linear regression and non-parametric Mann-Kendall tests. The results showed that only one station- the Station Saghez- has a decreasing trend in temperature; the others have increasing or no trends. Eleven stations showed increasing trends in temperature, while five stations had no significant trends. These results could be interpreted as climate change in the west of Iran.