Recently, technological development has become increasingly pronounced, with great advances in all production areas, including agriculture. In the agricultural sector, improvements in machinery and the study of new techniques have resulted in the increased efficiency and productivity of different crops. In particular, UAVs (unmanned aerial vehicles) are increasingly used in agriculture. Among the latest utilities is the application of phytosanitary products. The use of small UAVs retrofitted with spraying systems make it possible to treat large surfaces in short periods of time, achieving a reduction in inputs and time compared to conventionally used methods (trailed sprayers). The aim of this work was to compare conventional sprayers and UAV sprayers on a farm in Spain, with olive and vineyard crops. The determining factors in the choice of one or another alternative were studied, such as the economic requirements and efficiency of different alternatives. The results show that a large investment is required to acquire a UAV sprayer, while operating costs are higher for conventional sprayers versus UAV sprayers. Efficiency (ha/h) is much higher for UAV sprayers. In addition to these advantages, UAV sprayers require a lower cost of water and products. However, different factors could make conventional sprayers a better choice.