Objective: Gestational diabetes mellitus (GDM) is a common complication during pregnancy and if not managed properly, it can lead to many harmful effects on mother or fetus/baby. Management of GDM largely depends on patient’s thoughts, perception and understanding of disease. This study was conducted to evaluate the knowledge, attitude, and treatment satisfaction of GDM patients toward their disease. Methods: This was a descriptive cross‑sectional study conducted during the period of month July 2013 at Penang General Hospital, Penang, Malaysia. The sample consists of 30 established patients of GDM who were diagnosed at least 1 month prior to enrolment. Data were collected by means of self‑designed Gestational Diabetes Mellitus Knowledge Questionnaire, modified version of Diabetes Integration Scale (ATT‑19) and Diabetes Treatment Satisfaction Questionnaire. Descriptive analysis was used for data elaboration by using SPSS 20. Results: The results showed that of 30 patients, 23 patients (76.6%) had adequate knowledge. Only, 7 (23.3%) patients had inadequate knowledge. For attitude, 23 (76.66%) of patients had a negative attitude toward disease and only 7 (23.3%) had a positive attitude. In terms of satisfaction, 25 (83.33%) patients were satisfied with the given treatment and 5 (16.66%) were unsatisfied. Conclusion: We conclude that although participants obtained good score on knowledge and treatment satisfaction, their attitude did not change so as to more effectively cope with their disease.