Abstract Background Esketamine nasal spray (ESK) is approved, in conjunction with an oral antidepressant, for the treatment of treatment-resistant depression in adults and for the treatment of depressive symptoms in adults with major depressive disorder with acute suicidal ideation or behavior. No adverse events (AEs) of respiratory depression were reported in ESK phase 3 clinical trials; however, postmarketing incidents of respiratory depression associated with ESK use have been observed. Methods The Janssen Global Medical Safety (GMS) database was reviewed for cases meeting the criteria for respiratory depression with ESK using 47 months of postapproval data, based on the Standardized Medical Dictionary for Regulatory Activities (MedDRA) Query (SMQ) acute central respiratory depression (broad). FDA Adverse Event Reporting System (FAERS), EudraVigilance, and literature searches were performed to identify reports of respiratory depression related to ESK use. Results Fifty cases, representing 50 patients, in the GMS database met the case definition for respiratory depression; 8 of these had a stronger association with ESK use. The MedDRA preferred term (PT) hypopnea met the threshold for disproportionality with ESK in FAERS. The MedDRA PTs asphyxia, oxygen saturation decreased, respiratory depression, and apnea met the threshold for disproportionality with ESK in EudraVigilance. Conclusion Despite extensive soliciting of AEs for ESK with the US Risk Evaluation and Mitigation Strategy program, respiratory depression is infrequently observed with ESK treatment in the postmarketing setting (estimated incidence: 1 case per 20 000 treatment sessions). Symptoms are manageable and resolve with minor supportive measures. Monitoring for symptoms of respiratory depression, including pulse oximetry, is recommended within the postdose observation period.