We conducted a study to compare a standard anterosuperolateral (ASL) portal with a percutaneous Port of Wilmington (PW) portal for repair of superior labrum anterior and posterior (SLAP) tears. We hypothesized that anchors placed through the PW portal would be less likely to penetrate the glenoid or injure the suprascapular nerve (SSN). This study used 6 matched-pair cadaveric shoulders. Two anchors were arthroscopically placed posterior to the biceps, at 11 o'clock and 10 o'clock, to simulate a SLAP repair. One set of anchors was placed through an ASL portal and the other through a PW portal. Glenoid vault penetration and distance to SSN were noted. In the ASL portal group, 8 (66.7%) of 12 anchors violated the medial cortex of the glenoid; in the penetration cases, mean distance to SSN was 6.8 mm for 11 o'clock anchors and 4.8 mm for 10 o'clock anchors. In the PW portal group, 2 (16.7%) of 12 anchors violated the medial cortex of the glenoid; in the penetration cases, distance to SSN was 20 mm for the 11 o'clock anchor and 8 mm for the 10 o'clock anchor. The risk of glenoid vault penetration during repair of SLAP tears posterior to the biceps tendon is reduced when a percutaneous posterior approach is used for anchor placement. This approach also directs the anchor away from the SSN.