BACKGROUND It has been suggested that routine adrenal venous sampling (AVS) is necessary to lateralize an aldosterone-producing adenoma in patients with primary hyperaldosteronism. However, the success rate of AVS is variable, with potential risks. We review our experience at University of California San Francisco (UCSF), where AVS is used only selectively, to determine outcomes with this approach. METHODS All patients undergoing adrenalectomy for aldosteronoma at UCSF from January 1995 to October 2004 were included. Outcome after adrenalectomy was determined based on plasma levels of aldosterone and potassium, rates of persistent hypertension, and reduced use of antihypertensive medications. RESULTS Altogether, 65 patients were included in the study, 52 (80%) of whom had their adrenal tumors lateralized based on computed tomography scans, magnetic resonance imaging, or both. The remaining 13 (20%) patients had doubtful localization of their lesions on imaging. We did not routinely perform AVS in patients with definitive imaging findings. Thus, only 4 (8%) patients with definitive imaging findings underwent AVS, and one was unsuccessful. Of the 13 patients with doubtful lateralization on imaging, 8 underwent AVS. With this practice, biochemical cure rates after adrenalectomy were up to 100%, and hypertension resolved or was improved in 85% of patients. CONCLUSIONS AVS may be performed selectively only when preoperative imaging cannot definitively lateralize the aldosteronoma. This practice in our center has resulted in high cure rates. During the era of improved imaging resolution and experience, mandatory routine AVS is not necessary to achieve high cure rates for aldosteronomas.