Objective: Transsphenoidal surgery (TSS) is a first-line treatment for Cushing disease (CD). However, a subset of patients with CD have no visible adenoma on magnetic resonance imaging (MRI), and whether MRI results affect surgical outcomes is controversial. The aim of this study was to compare the surgical outcomes of CD patients with negative MRI findings to those of patients with positive MRI findings. Methods: The clinical features and outcomes of CD patients who underwent TSS between January 2000 and July 2019 at Peking Union Medical College Hospital were collected from medical records. The clinical, endocrinologic, histopathologic, surgical outcomes, and a minimum 12-month follow-up of 125 consecutive CD patients with negative MRI findings were compared with those of 1,031 consecutive CD patients with MRI-visible adenomas. Results: The total remission rate was 73.3% after TSS, and 11.8% of patients experienced recurrence. Of 1,031 patients with MRI-visible adenomas, postoperative remission was achieved in 762 patients (73.9%), and the recurrence of CD was observed in 94 (12.3%) patients. Of the 125 patients with negative MRI findings, postoperative remission was achieved in 85 (68%) patients, and recurrence was observed in 6 (7.1%) patients. The remission rate and recurrence rate were not significantly different between patients with negative MRI findings and those with positive MRI findings (all P>.05). The remission rate was not significantly different between patients who did or did not undergo bilateral inferior petrosal sinus sampling (BIPSS) in patients with negative MRI findings (P>.05). In the patients with negative MRI findings who underwent BIPSS, the remission rate of patients with positive BIPSS results was not different from that in patients with negative BIPSS results (P>.05). The lack of prior TSS, the detection of a tumor during operation, and pathologic confirmation of adenoma were associated with a higher surgical remission rate in patients with negative MRI findings (all P<.05). Similar results were observed in the patients with positive MRI findings (all P<.05). In addition, the major perioperative complications, including intraoperative cerebrospinal fluid leakage, hypopituitarism, and transient diabetes insipidus, were not related to the MRI results (all P>.05). Conclusion: The remission rate and recurrence rate were not different between patients with negative MRI findings and those with positive MRI findings. If CD is clearly diagnosed according to biochemical tests, radiologic examinations, and BIPSS, we recommend TSS as the first-line treatment for patients, even if the MRI results arc negative.