Emerging evidence suggests that synaptic dysfunction occurs prior to neuronal loss in neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS). Therefore, monitoring synaptic activity during early stages of neurodegeneration may provide valuable information for the development of diagnostic and/or therapeutic strategies. Here, we describe an electrophysiological method routinely applied in our laboratory for investigating synaptic activity of the neuromuscular junction (NMJ), the synaptic connection between motoneurons and skeletal muscles. Using conventional intracellular sharp electrodes, both spontaneous synaptic activity (miniature end-plate potentials) and evoked synaptic activity (end-plate potentials) can be readily recorded in acutely isolated nerve-muscle preparations. This method can also be adapted to various simulation protocols for studying short-term plasticity of neuromuscular synapses.