Drought is a common climate phenomenon for the territory of Bulgaria, which has a negative impact on agriculture and water resources. Taking into account the undetermined character of drought in regard to drought occurrence, severity and impact the present study proposes a fuzzy logic approach to complex drought vulnerability assessment. The assessment is based on multifactorial analysis integrating climatic (precipitation and air temperature) and non-climatic (distance from the water objects, aspects and soil types) factors for drought occurrence as well as anthropogenic factors (land use types) in order to determine drought susceptibility and vulnerability. In this study, the fuzzy logic model is designed as a three-level hierarchical system with four inputs and one output. Each level of the hierarchical system is consisted of one fuzzy logical subsystem with two inputs. The results of the simulations performed with developed fuzzy logic system using actual data show the importance of climatic factors for drought susceptibility while drought vulnerability depends mainly of anthropogenic factors. The areas with the same susceptibility to drought may have different degrees of vulnerability depending on the type of land use and the number of people affected. The fuzzy logic model is useful for a comprehensive drought assessment, especially for areas for which available data are insufficient.