Background Becoming a mother of newborn involves adaptation to may changes socially and physiologically. Some risk factors are responsible for the development of postpartum psychosis including postpartum hormonal changes. Objectives: was to study the role of thyroid dysfunction in development of early postpartum psychosis among a sample of Egyptian women. Subjects and Methods: A total of 60 female patients with postpartum psychosis during the first four weeks after delivery not suffering from any previous psychiatric disorders (Case Group) and 30 female patients within the first four weeks after delivery not suffering any psychiatric disorders (Control Group) were subjected to clinical psychiatric assessment using structured psychiatric interview of DSM -V, BPRS, HDRS and measuring plasma level of thyroid hormones e.g., free triiodothyronine, free tetra-iodothyronine and thyroid stimulating hormone. Results: There were higher significant difference regarding thyroid dysfunction in patients with postpartum psychosis than in controls. Patients with postpartum psychosis with thyroid dysfunction have a higher significant score on BPRS and HDRS than patients with postpartum psychosis without thyroid dysfunction. Conclusion: There is significant association between thyroid dysfunction in first four weeks after delivery and postpartum psychosis.