This study investigated miRNA and cytokine expression changes in peritoneal fluid samples of patients with advanced ovarian cancer (OVCA) after receiving hyperthermic intraperitoneal chemotherapy (HIPEC) during cytoreduction surgery (CRS). We collected samples prior to HIPEC, immediately after HIPEC, and 24/48/72 h after CRS from a total of 6 patients. Cytokine levels were assessed using a multiplex cytokine array, and a miRNA PanelChip Analysis System was used for miRNA detection. Following HIPEC, miR-320a-3p, and miR-663-a were found to be immediately down-regulated but increased after 24 h. Further, significant upregulation post-HIPEC and sustained increases in expression were detected in six other miRNAs, including miR-1290, miR-1972, miR-1254, miR-483-5p, miR-574-3p, and miR-574-5p. We also found significantly increased expression of cytokines, including MCP-1, IL-6, IL-6sR, TIMP-1, RANTES, and G-CSF. The changing expression pattern throughout the study duration included a negative correlation in miR-320a-3p and miR-663-a to cytokines including RANTES, TIMP-1, and IL-6 but a positive correlation in miRNAs to cytokines including MCP-1, IL-6sR, and G-CSF. Our study found miRNAs and cytokines in the peritoneal fluid of OVCA patients demonstrated different expression characteristics following CRS and HIPEC. Both changes in expression demonstrated correlations, but the role of HIPEC remains unknown, prompting the need for research in the future.