Abstract Background Reduced port laparoscopic surgery (RPLS) is comparable to conventional multiport laparoscopic surgery and has the potential to provide improved cosmesis and decreased pain; as such, it satisfies a growing demand for less invasive surgical procedures. Moreover, a zigzag incision of the umbilicus results in a less visible scar in plastic surgery. Here we report a series of two cases with bilateral organ tumors treated by single-stage RPLS using a combination of a transumbilical approach and a zigzag incision. Case presentation Case 1: A 63-year-old man was diagnosed with right renal cell carcinoma (RCC) (clear cell carcinoma, pT1a, venous invasion (−)) and a splenic tumor (cavernous hemangioma). Case 2: An 84-year-old woman was diagnosed with concurrent left RCC (clear cell carcinoma, pT1b, 65 × 65 mm, venous invasion (+)) and ascending colon cancer (adenocarcinoma pT3 with no nodal involvement (0/48)). The perioperative course was uneventful in both cases. However, an additional incision was required in Case 2 for specimen excision. Therefore, the scars were more obvious in Case 2 than in Case 1. Conclusions Although more cases are required to evaluate the superiority of this technique, this novel procedure could be considered for patients with bilateral lesions.