OBJECTIVE: To investigate the feasibility, oncological efficacy and safety of robotic segmental ureterectomy (SU) for treating patients with localised upper tract urothelial carcinoma (UTUC). A key aspect of this research involves utilising Black Eye™ Endoscopic Marker Ink to delineate the boundary of the tumour in the ureter, helping to ensure precise surgical intervention and reducing the risk of positive surgical margin. PATIENTS AND METHODS: In a prospective non-randomised trial from January 2018 to December 2022, patients with localised UTUC confirmed by CT-urography were enrolled. A Multidisciplinary Team assessed patients for suitability for kidney-sparing surgery (KSS) with SU, marked by endoscopic Black Eye™ Endoscopic Marker Ink. Black Eye Endoscopic Marker Ink marking aimed to enhance surgical precision by delineating clear resection margins. The primary endpoints were the feasibility of the technique, local and bladder recurrence rates and surgical outcomes. Propensity score matching was used for a balanced comparison to the standard treatment Radical Nephroureterectomy (RNU). RESULTS: Thirty patients underwent SU, in the period of study with only one local recurrence reported with a median follow-up time of 35 months. SU was associated with a significantly shorter operative time (41 minutes less on average, CONCLUSION: SU with Black Eye™ Endoscopic Marker Ink marking is a viable KSS technique that offers a safe and effective alternative to RNU for patients with a single tumour, no longer than 30 mm and of low grade. This novel approach is promising in lowering the risk of positive margins, ensuring cancer control and preserving renal function.