Background: Studies on the associations between preoperative cerebral edema, cognitive functioning, and health-related quality of life (HRQOL) in WHO grade I meningioma patients are virtually lacking. We studied the association between preoperative cerebral edema on postoperative cognitive functioning and HRQOL 6 months postoperatively in WHO grade I meningioma patients. Methods: Twenty-one consecutive WHO grade I meningioma patients, who underwent surgery, were matched individually for age, gender, and educational level to healthy controls. Tumor and edema volume were assessed on preoperative T1- and T2-weighted MRI images, respectively. At least 5 months postoperatively, functional status, cognitive functioning, and HRQOL, using a cognitive test battery and the Short-Form Health Survey (SF-36), were determined. The correlation between preoperative tumor and cerebral edema volume with postoperative cognitive functioning and HRQOL was investigated using Kendall’s tau coefficients. Results: Compared to healthy controls, patients had lower verbal memory capacity (p =.012), whereas HRQOL was similar to matched healthy controls. In all cognitive domains, postoperative functioning was much lower in patients with preoperative cerebral edema than in those without. There were significant correlations between preoperative cerebral edema and tumor volume and postoperative cognitive functioning. Preoperative cerebral edema and/or tumor volume were not associated with HRQOL. Conclusions: Our results suggest that WHO grade I meningioma patients with larger volumes of preoperative cerebral edema are more at risk of experiencing limitations in longer-term cognitive functioning than patients with no or less edema preoperatively. This is an important knowledge for neurologists and neurosurgeons treating patients with a meningioma. More studies regarding the effect of peritumoral edema on cognitive functioning in meningioma patients are necessary.