Background: Thyroidectomy is the surgical removal of a partial or complete thyroid gland in case of hyperthyroidism, thyroid cancer and goiter. The aims of this study: were to eveluate effect of designed nursing guidelines on minimizing postoperative complications for patients undergoing thyroidectomy through the following; 1) assess patients' knowledge and practice about thyroidectomy, 2) design nursing guidelines , 3) evaluate the effect of applying these guidelines on minimizing postoperative complications for patients undergoing thyroidectomy. Patients and method: This study was conducted in the general surgery department and outpatient surgery clinic at Assiut University Hospital. A convientent sample of 60 adult patients of both sexes, their ages ranged between 20 - 65 years old and were divided into two equal groups (study and control) thirty patients for each. Tools: Patient assessment sheet and thyroidectomy complications evaluation sheet. Results: there was statistically significant difference between the study and control groups regarding knowledge and practice scores, wound healing and other thyroidectomy complications. Conclusion: implementation of the designed nursing guidelines in the management of patients undergoing thyroidectomy had improved patients' outcomes: significantly increased level of knowledge and practice scores, and decreased overall postoperative complications rate. Recommendation: Providing a written instruction booklet about perioperative care for thyroidectomy is of great importance for the patients.