Agricultural unmanned aerial vehicles and the Internet of Things are of vital importance for precision agriculture applications. The use of agricultural UAV systems is one of the most important commercial UAV usage areas. The use of UAVs for agricultural purposes includes obtaining data to be used in precision agriculture by remote sensing. Applications such as disease and pest detection in plants, water stress detection, yield/maturity estimation and weed detection can be carried out with remote sensing. Remote sensing is the most important factor for precision agriculture. UAV systems and IoT technologies are used for remote sensing. Today, with the development of UAV-based remote sensing systems, remote sensing and precision agriculture can be easily implemented. UAV systems are used to monitor crops. Compared to other methods, it offers many opportunities to obtain field data easily, quickly and cost-effectively. The ability of UAVs to fly at low altitudes allows ultra-high-resolution images of crops to be obtained. This significantly improves the performance of monitoring systems. Visulation sensors such as Visible RGB, Near Infrared (NIR), Multispectral, Hyperspectral, Thermal, Laser scanners (LiDAR) and Synthetic Aperture Radars (SAR) are used for precision agriculture in nowadays. In this study, examples of agricultural uses of UAV systems were evaluated and examples of the use of UAV systems in precision agriculture were given. At the same time, the use of UAV systems in the use of remote sensing was explained.