Background: Endometrial cancer is the most common gynaecological cancer and has a strong association with obesity. Surgical site infection (SSI) carries high morbidity and is more frequent in obese patients. Closed incision negative pressure wound therapy (ciNPWT) has been proposed to reduce wound morbidity but is more expensive than standard dressings whilst the evidence has been very heterogenous. There is limited evidence to justify this expensive dressing as related to its effectiveness in gynaecological oncology patients. ciNPWT was introduced in New Zealand in 2017 based on the available evidence from studies on SSI in the obstetric population. The aim of this study is to investigate the rate of SSI in patients with endometrial carcinoma undergoing laparotomy using standard surgical dressings compared to ciNPWT. Methods: We performed a retrospective analysis of 170 patients who underwent a laparotomy for endometrial carcinoma between 2018 and 2019 across three hospitals in New Zealand after the introduction of ciNPWT. Dressings were applied according to individual surgeons’ preferences. Standard dressings and ciNPWT were compared in the occurrence of SSI, wound dehiscence, readmission and return to theatre rates using logistic regression in order to account for potential confounding due to the patient demographics and oncologic and surgical characteristics. Results: There were 129 patients in the standard dressing group and 41 patients in the ciNPWT group. The mean age was 60.4 years (range 25–86). The mean body mass index (BMI) was 38.2 kg/m{}^2 (range 20–69 kg/m{}^2). The percentage of patients who experienced a SSI was higher in the ciNPWT group (34.2% vs. 20.9%; p = 0.159). There was no significant difference between the dressing groups in the occurrence of superficial SSI rate, return to theatre, or readmission. Wound dehiscence and deep/organ space SSI were however worse with ciNPWT (adjusted odds ratio (aOR) 4.09 and aOR 7.19, respectively). Conclusions: This study demonstrated no evidence for the benefit of ciNPWT, and higher rates of deep/organ space SSI. More randomised trials are needed to investigate whether gynaecological oncology patients may benefit from ciNPWT thus justifying the extra cost of this dressing.