Robotic-assisted pyeloplasty (RAP) is a mainstay in the treatment of ureteropelvic junction obstruction (UPJO) in children. At our institution, to limit planned operating rooms visits we have placed a ureteral stent with an external string (SWES) immediately prior to RAP. In this study, we sought to quantify the operative time, complications, and costs associated with this approach compared to the traditional approach, requiring subsequent stent removal in the operating room. We hypothesized the SWES cohort would have decreased cost, yet with similar operative time and complications. We retrospectively collected all RAPs performed at our institution using the SWES approach (Aug 2012-July 2017). We excluded those with a redo pyeloplasty, and/or a percutaneous nephrostomy tube for post-operative drainage. We collected 30-day costs linked to the patients' MRN using the Pediatric Health Information System (PHIS) database. We compared 30-day healthare costs for all patients following RAP. We compared our SWES group to a national cohort of all pediatric RAP during the same time period. Lastly, we sent an anonymous, electronic survey to urologists of all PHIS institutions to identify the predominant postoperative drainage, nationally. Within our institution, we reviewed all those treated with SWES (n = 85) (Table 1). The median 30-day cost was $10,548 among those with SWES (Table 2). This was significantly less than the overall, national cohort of all pediatric RAP during the same period ($14,119, p < 0.001). There was a 15.5 % rate of unplanned return to the hospital in the SWES group. Of those unplanned returns, 8.2 % (7/85) had unplanned return for a procedure (3 for unplanned stent removal, 2 for nephrostomy tube for persistent obstruction, 1 for omental hernia, and 1 for stent replacement). With a 42.5 % (37/87) response rate, our nationwide survey found 84.6 % primarily leave stents WITHOUT a string, 7.7 % left nephrostomy tubes, and 7.7 % stents with strings. During pediatric RAP, placement of a SWES takes little time, carries a risk of unplanned visit to the operating room, saves the patient a certain, second anesthetic for stent removal, and amounts to a cost savings of approximately 25 %.