We evaluated the use of the Edinburgh Postnatal Depression Scale (EPDS) as a screening tool to prevent the misdiagnosis of Postpartum Depression (PPD). The Stetler Model (SM) was used to guide implementation of the EPDS in an ambulatory psychiatric setting for this quality improvement (QI) project. Women diagnosed with PPD during an eight-week period immediately prior to the implementation of the EPDS were compared with women diagnosed with PPD using the EPDS during an eight-week period. The final sample of participating key stakeholders included three Psychiatrists (MD) and one Nurse Practitioner (NP) that agreed to implement the EPDS. A total of 29 pre- and post implementation postpartum women (PPW) met inclusion criteria for this project making up the final sample size. Eight were not screened by the EPDS during the two-week period prior to its implementation. A total of 21 postpartum women were screened with implementation of the EPDS. Of those PPW, 21 (100%) were diagnosed with PPD compared to six/eight (75%) PPW diagnosed with PPD without the use of the EPDS. Participating MDs and the NP diagnosed two (25%) patients with non-postpartum depression and anxiety when the EPDS was not used. Screening for postpartum depression with a tool that supports measurement of symptoms may help to more accurately diagnose PPD, and thus with more appropriate treatment of PPD.