BACKGROUND: It has been suggested that in comparison with open radical cystectomy, robotic-assisted radical cystectomy results in less blood loss, shorter convalescence, and fewer complications with equivalent short-term oncological and functional outcomes; however, uncertainty remains as to the magnitude of these benefits. OBJECTIVES: To assess the effects of robotic-assisted radical cystectomy versus open radical cystectomy in adults with bladder cancer. SEARCH METHODS: Review authors conducted a comprehensive search with no restrictions on language of publication or publication status for studies comparing open radical cystectomy and robotic-assisted radical cystectomy. The date of the last search was 1 July 2018 for the Cochrane Central Register of Controlled Trials, MEDLINE (1999 to July 2018), PubMed Embase (1999 to July 2018), Web of Science (1999 to July 2018), Cancer Research UK (www.cancerresearchuk.org/), and the Institute of Cancer Research (www.icr.ac.uk/). We searched the following trials registers: ClinicalTrials.gov (clinicaltrials.gov/), BioMed Central International Standard Randomized Controlled Trials Number (ISRCTN) Registry (www.isrctn.com), and the World Health Organization International Clinical Trials Registry Platform. SELECTION CRITERIA: We searched for randomised controlled trials that compared robotic-assisted radical cystectomy (RARC) with open radical cystectomy (ORC). DATA COLLECTION AND ANALYSIS: This study was based on a published protocol. Primary outcomes of the review were recurrence-free survival and major postoperative complications (class III to V). Secondary outcomes were minor postoperative complications (class I and II), transfusion requirement, length of hospital stay (days), quality of life, and positive margins (%). Three review authors independently assessed relevant titles and abstracts of records identified by the literature search to determine which studies should be assessed further. Two review authors assessed risk of bias using the Cochrane risk of bias tool and rated the quality of evidence according to GRADE. We used Review Manager 5 to analyse the data. MAIN RESULTS: We included in the review five randomised controlled trials comprising a total of 541 participants. Total numbers of participants included in the ORC and RARC cohorts were 270 and 271, respectively.Primary outomesTime-to-recurrence: Robotic cystectomy and open cystectomy may result in a similar time to recurrence (hazard ratio (HR) 1.05, 95% confidence interval (CI) 0.77 to 1.43); 2 trials; low-certainty evidence). In absolute terms at 5 years of follow-up, this corresponds to 16 more recurrences per 1000 participants (95% CI 79 fewer to 123 more) with 431 recurrences per 1000 participants for ORC. We downgraded the certainty of evidence for study limitations and imprecision.Major complications (Clavien grades 3 to 5): Robotic cystectomy and open cystectomy may result in similar rates of major complications (risk ratio (RR) 1.06, 95% CI 0.76 to 1.48); 5 trials; low-certainty evidence). This corresponds to 11 more major complications per 1000 participants (95% CI 44 fewer to 89 more). We downgraded the certainty of evidence for study limitations and imprecision.Secondary outcomesMinor complications (Clavien grades 1 and 2): We are very uncertain whether robotic cystectomy may reduce minor complications (very low-certainty evidence). We downgraded the certainty of evidence for study limitations and for very serious imprecision.Transfusion rate: Robotic cystectomy probably results in substantially fewer transfusions than open cystectomy (RR 0.58, 95% CI 0.43 to 0.80; 2 trials; moderate-certainty evidence). This corresponds to 193 fewer transfusions per 1000 participants (95% CI 262 fewer to 92 fewer) based on 460 transfusion per 1000 participants for ORC. We downgraded the certainty of evidence for study limitations.Hospital stay: Robotic cystectomy may result in a slightly shorter hospital stay than open cystectomy (mean difference (MD) -0.67, 95% CI -1.22 to -0.12); 5 trials; low-certainty evidence). We downgraded the certainty of evidence for study limitations and imprecision.Quality of life: Robotic cystectomy and open cystectomy may result in a similar quality of life (standard mean difference (SMD) 0.08, 95% CI 0.32 lower to 0.16 higher; 3 trials; low-certainty evidence). We downgraded the certainty of evidence for study limitations and imprecision.Positive margin rates: Robotic cystectomy and open cystectomy may result in similar positive margin rates (RR 1.16, 95% CI 0.56 to 2.40; 5 trials; low-certainty evidence). This corresponds to 8 more (95% CI 21 fewer to 67 more) positive margins per 1000 participants based on 48 positive margins per 1000 participants for ORC. We downgraded the certainty of evidence for study limitations and imprecision. AUTHORS' CONCLUSIONS: Robotic cystectomy and open cystectomy may have similar outcomes with regard to time to recurrence, rates of major complications, quality of life, and positive margin rates (all low-certainty evidence). We are very uncertain whether the robotic approach reduces rates of minor complications (very low-certainty evidence), although it probably reduces the risk of blood transfusions substantially (moderate-certainty evidence) and may reduce hospital stay slightly (low-certainty evidence). We were unable to conduct any of the preplanned subgroup analyses to assess the impact of patient age, pathological stage, body habitus, or surgeon expertise on outcomes. This review did not address issues of cost-effectiveness.