Objectives: Though identification of underlying anatomical causation and surgical management of is the mainstay of treatment, needle aspiration with or without injection of corticosteroid is a common conservative management for enlarged and painful Baker's cysts (BC). This report explores some of the circumstances in which ultra-sound guided BC aspiration may be a first-line option. Methods: A 46 year-old recreational athlete developed marked posterior knee pain and swelling several years after arthroscopic medial meniscal debridement. Needle aspiration of a large & symptomatic BC was performed under ultrasound guidance, and the patient commenced rehabilitation. Results: Posterior knee pain completely abated post procedure. Increased knee joint flexion, and squatting was sustained, without cyst recurrence on 6 month follow-up. Conclusion: Ultrasound-guided aspiration of painful or enlarged Bakers cyst may have sustained benefits after knee arthroscopy in the older athlete, particularly in cases when no further surgery is indicated or planned. Diagnostic ultrasound differentiates BC from other types of masses, provides real-time dynamic visualization of the popliteal neurovascular bundle, guides needle placement, and helps to insure complete BC aspiration, accurate injection, and fenustration. BC aspiration, may also be indicated in cases of operative delay, comorbidities contraindicating surgery, to facilitate rehabilitation, or when the underlying causation of BC is indeterminate. Large cysts causing neurovascular compression may require more emergent aspiration. As this case report illustrates, symptomatic relief and functional improvements may be sustained for several months.