<b><i>Purpose:</i></b> This study aimed to explore the complication rates of radical cystectomy in patients with muscle-invasive bladder cancer and identify potential risk factors. <b><i>Methods:</i></b> A total of 553 patients were included: 131 were operated on via an open approach (ORC), 242 patients via a laparoscopic method (LRC), and 180 by a robot-assisted procedure (RARC). Patient age, gender, American Society of Anesthesiologists (ASA) score, urinary diversion type, preoperative albumin level, body mass index (BMI), pathological (TNM) stage, and surgical times were collected. The severity of complications was classified according to the Clavien-Dindo scale (Grades 1–5). <b><i>Results:</i></b> The surgical technique was significantly related to the number of complications (<i>p</i> < 0.00005). Grade 1 complications were observed most frequently following LRC (52.5%) and RARC (51.1%), whereas mostly Grade 2 complications were detected after ORC (78.6%). Those with less severe complications had significantly higher albumin levels than those with more severe complications (<i>p</i> < 0.05). Patients with an elevated BMI had fewer complications if a minimally invasive approach was used rather than ORC. The patient’s general condition (ASA score) did not impact the number of complications, and urinary diversion type did not affect the severity of the complications. Mean surgical time differed according to the urinary diversion type in patients with a similar TNM stage (<i>p</i> < 0.005); however, no difference was found in those with more locally advanced disease. Longer operation time and lower protein concentration were associated with higher probability of complication rate, that is, Clavien-Dindo score 3–5. <b><i>Conclusions:</i></b> The risk of complications after RC is not related to the type of urinary diversion, and can be reduced by using a minimally invasive surgical technique, especially in patients with high BMI.
