Flies use visual cues for a variety of tasks, such as maneuvering through the environment and finding potential mates. Hoverflies, in particular, have very developed eyes and use them to be able to hover mid air and perform fast, elegant movements. The Motion Vision Group, located at the Department of Neuroscience at BMC, Uppsala, studies the motion vision system of the hoverfly brain, using electrophysiology. Experiments are performed by displaying visual stimuli on a screen in front of an immobilized fly, while recording the response from a single neuron with a thin electrode.Until now, the Motion Vision group has been using the open source program VisionEgg to generate the stimuli. VisionEgg is able to display stimuli at high frame rate and has a large set of useful features such as perspective distortion. It also has a lot of drawbacks that makes it desirable to acquire new software. The main drawbacks include it being hard to learn, use and modify, as well as being unable to generate the stimuli needed for some key experiments.This master´s thesis describes the development of software more suited to the lab´s needs. This software should be able to generate some of the stimuli that were impossible to do at the moment, as well as being easy to expand and add upon. The frame rate of the displayed stimuli has to be both high and stable in order to perform high precision experiments.The resulting program is called FlyFly and has been developed iteratively in close cooperation with its end users, ensuring a user friendly end product capable of meeting the lab´s needs. FlyFly is implemented using MatLab and the Psychophysics toolbox with the graphical user interface (GUI) designed with the Guide editor. The GUI is decoupled from the functions drawing the stimuli, making it easy to improve or remove parts altogether. FlyFly is intuitive to use and allows anyone to quickly get started. It allows easy manipulation of series of trials, and supports drawing of multiple objects simultaneously. With the current machine set-up, it displays stimuli at 160 frames per second with few or no dropped frames.FlyFly is currently being used in the lab and will be so for the foreseeable future.