Objectives: We report nine cases of primary ovarian non-Hodgkin’s lymphoma (PONHL). Materials and methods: From January 2000 to February 2020, we retrospectively analyzed nine patients with PONHL admitted to our hospital. Their clinicopathologic features, treatments, and outcomes were summarized. Results: This study included eight cases of DLBCLs and one case of T-cell origin. Their presentations included abdominal pain, abdominal distension, and a pelvic mass, and one had a history of B symptoms. Imaging features revealed large, solid, and homogenous adnexal lesions. Four cases had bilateral ovary involvement and one had abdominal bloody ascites. Intraoperative frozen section analysis showed that five patients had lymphoma, and four had incorrect diagnoses. All patients received surgical treatment and adjuvant chemotherapy. Three patients died of their disease, and six are alive and cancer-free. Conclusions: Preoperative diagnosis of PONHL is difficult. Correct frozen section analysis is a key determinant for guiding conservative therapy. Adjuvant R-CHOP chemotherapy might be an effective regimen.