Over the last two decades, the Drosophila larval neuromuscularjunction has gained immense popularity as a model system forthe study of synaptic development, function, and plasticity.With this model, it is easy to visualize synapses and manipulatethe system genetically with a high degree of temporal and spatialcontrol, which makes it ideal for resolving problems in synapticphysiology and development. This article describes the preparationof Drosophila larval body-wall muscles for imaging by electronmicroscopy. The samples are fixed, stained, and embedded inSpurr’s resin before being sectioned for electron microscopy.