Successful catheter ablation of atrial fibrillation (AF) requires a detailed understanding of left atrial anatomy in order to maximize the safety and efficacy of the procedure. Common and rare variants of left atrial and pulmonary venous anatomy have been described which can affect the optimal ablation strategy for each individual patient. These variants include the presence of a right or left middle pulmonary vein, a left or right common pulmonary vein, a common inferior pulmonary vein, a right top pulmonary vein, and other rare forms of anomalous pulmonary venous drainage. There are also important patient-specific differences in pulmonary venous ridges and left atrial roof morphology. Pre-procedural CT or MR imaging can define these anatomic variants in exquisite detail and be used with image-integration strategies to direct the ablation procedure. In this review, we describe common and uncommon variants that can be identified by pre-procedural imaging, and suggest ablation strategies tailored to these anatomic variants.