Selective venous sampling for PTH (SVS) is an invasive diagnostic imaging technique, indicated in patients with persistent or recurrent hyperparathyroidism when noninvasive imaging modalities are unhelpful in the localization of a pathological parathyroid gland. Crucial to the success of the procedure are the expertise of the operator and the collection of 20–30 samples from closely located sites in neck and mediastinal veins. This ensures sampling from all potential parathyroid venous drainage areas, including ectopic locations. In contemporary series, accuracy of SVS ranges from 75% to 95% and is enhanced by superselective sampling and using real-time quick PTH assays during the procedure and by combining SVS with 4D CT scans. Sensitivity of SVS is affected by the size of the pathological gland, its anatomical location and pathology, and number of previous surgeries. Although evidence for the localizing value of SVS before reoperation is primarily based on case series and small observational studies, this imaging modality has stood the test of time.