According to the statistics reported by The International Disaster Database, drought is the major natural disaster that has affected several countries from 1900 to early 2011. Therefore accurate and applicable drought monitoring methods are of importance for short and long term regional drought forecasting and disaster management in these countries, especially for agricultural and food production. This study aims at finding, evaluating and refining an appropriate agricultural drought estimation method for semi-arid regions, e.g. Iran using remote sensing techniques. Recently developed methods, the Perpendicular Drought Index (PDI) and Modified Perpendicular Drought Index (MPDI) that are derived from MODIS satellite images, were evaluated at selected agricultural sites in different agro-climatic zones in Iran to detect the severity of drought phenomena related to temporal variation and different climatic conditions. Because of the semi-arid and arid conditions found throughout Iran and considering winter wheat is a major agricultural crop in Iran, a combination of both the PDI (for partly covered vegetated areas) and MPDI (for fully covered vegetated areas) can be used as a simple and cost-efficient agricultural drought indices. This finding has potential significance for agricultural crop growing regions in other developing countries with similar climatic conditions.