Analyzing electrocardiographic (ECG) recordings, making a diagnosis and assessment of any arrhythmias present, is an important part of the workup of many equine cases. Accurate analysis requires a good-quality recording, free of as many artifacts as possible, with clear P-QRS-T complex morphology. For sustained arrhythmias, short-term recordings are sufficient to make the appropriate diagnosis before instigating treatment. Longer-term recordings are essential for arrhythmias that are paroxysmal, intermittent, or occurring infrequently, while exercising ECGs are required for arrhythmias associated with physical activity. A stepwise, logical approach to ECG analysis will help the observer to recognize and correctly diagnose any arrhythmias present.