In this study, by using the Mann-Kendall nonparametric method and Sen' sEstimator slope test, the trend of some elements including precipitation, average of maximum and minimum temperature and the number of snowydays Chaharmahal and Bakhtiari Province covers part of Zagros andZardkohe-Bakhtiari highlands, from which three major rivers includingZayandehrud, Dez and Karun originate. in an annual and monthly scale, wasevaluated in the stations of the province during a period of 30 years (1986-2015). The output was presented in the form of tables, graphs and iso-trendmaps as drawn in the Arc_GIS. The results showed that although changes inrainfall did not follow any specific trend in most months of the year, theamount of precipitation in the stations of Koohrang as the rainiest station inthe Province, Lordegan and Yan-Cheshme had a decreasing trend at thesignificance level of 99%; also, the the number of snowy days during Marchshowed a decreasing trend in Koohrang station. However, the averageminimum and maximum temperature in most areas of the province, in bothmonthly and yearly scales, except for the months of November andDecember, had a significantly increasing trend.