Background <p>Goblet cell adenocarcinoma (GCA) of the appendix with peritoneal metastases poses treatment challenges. Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) offers a potentially curative approach. This study evaluates outcomes in patients with appendiceal GCA undergoing CRS/HIPEC.</p> Methods <p>We retrospectively analyzed 92 patients with GCA and peritoneal metastases treated by CRS/HIPEC. Tumour markers were assessed preoperatively. All underwent midline laparotomy and peritoneal cancer index (PCI) calculation. Mitomycin C (10 mg/m²) HIPEC was perfused for 60 min at 42–43 °C. Immediate and long-term outcomes were analyzed.</p> Results <p>Mean age was 58 years; 35% male. Tumours were classified by Tang criteria: Tang A (2), Tang B (39), Tang C (40), and 11 unclassified. Mean operative time was 7 hours; mean PCI was 18. Complete cytoreduction (CC 0–1) was achieved in 67%. No perioperative mortality occurred. Postoperative complications occurred in 64%, with 6% grade 3/4. Median follow-up was 88 months. PCI &lt;&#xa0;20 had median overall survival (OS) of 34 months versus 11 months for PCI &gt;&#xa0;20 (<i>p</i> &lt; 0.0001). Median OS was 30 months in CC 0–1 versus 11 months in CC 2–3 (<i>p</i> = 0.0004). Median progression-free survival in CC 0–1 was 13 months. Positive lymph nodes were found in 67%, with no significant OS difference. Elevated CA125 (&gt;&#xa0;3× normal) predicted poorer prognosis (median OS 9 vs. 29 months; <i>p</i> = 0.0116). Overall median OS was 23 months; 5-year survival was 14%.</p> Conclusion <p>CRS and HIPEC provide 14% 5-year survival for GCA with peritoneal metastases. Complete cytoreduction, especially with PCI &lt;&#xa0;20, improves outcomes.</p>