Objectives: The aim of this study is to find out the prevalence and the demographic variables of hypothyroidism in Saudi women with heart failure, and the impact of hypothyroidism on systolic and diastolic function in relation to non-hypothyroidism group. Subjects and Methods: The study was conducted on 111 Saudi women with heart failure; all of them were subjected to complete medical history and clinical examination including complete cardiac clinical examination, ECG, Echo, blood pressure measuring as well as thyroid examination. Laboratory examination was performed to detect levels of TSH, T3, T4, Hb, HCT, urea, creatinine, TCL, TG, LDL and HDL. Results: About one third of S.A. women with heart failure had hypothyroidism and showed statistically significant difference (P