Objective: This study aimed to evaluate the usability of peritoneal swabbing cytology (PSC) with cotton swabs as an effective method for the detection of peritoneal metastasis during the staging laparotomy of epithelial ovarian carcinomas and borderline tumours (EOC/BT). Study Design: One hundred and ninety-two patients with EOC/BT who underwent laparotomy at the Yokohama City University Hospital from 2004 to 2010 were analysed retrospectively. The positive rates of the PSC and ascites/peritoneal-wash cytology (A/PWC) were compared. Results and Conclusion: Both A/PWC and PSC were performed during laparotomy (n = 140). The rate of metastasis detection with A/PWC was significantly higher than with PSC (50.0 vs. 20.7%, p < 0.001 by χ2 test). The superior detection ability of A/PWC was observed regardless of the presence of macroscopic peritoneal metastasis in 56 cases with macroscopic peritoneal metastasis, with A/PWC detecting 80.3% of cases versus PSC detecting 37.5% (p = 0.013). In 84 cases without macroscopic peritoneal metastasis, A/PWC detected 29.8% of cases versus 9.5% with PSC (p = 0.003). Our results suggest that PSC is insufficient to evaluate the peritoneal metastasis for the surgical staging of EOC/BT. Other procedures such as subdiaphragmatic A/PWC should be included when possible to maximize the accuracy of diagnosis.