This study was performed to illustrate the potential relationship between reduced serum and local LncRNA MALAT1 expressions with disease severity in patients with non-traumatic osteonecrosis of the femoral head (ONFH). A total of 104 patients with non-traumatic ONFH and 100 healthy controls were consecutively recruited from our hospital. Serum and local LncRNA MALAT1 expressions were detected using real-time polymerase chain reaction (RT-PCR). Radiographic progression was defined by Ficat classification. Clinical severity was evaluated by Visual Analog Scale (VAS) and Harris Hip Score (HHS). Receiver operating characteristic (ROC) curve was carried out to determine the diagnostic value of MALAT1 in the radiographic progression. Serum LncRNA MALAT1 expressions were significantly lower in non-traumatic ONFH patients than in healthy controls. In addition, local MALAT1 expressions in non-traumatic ONFH tissue were significantly lower in the affected area than in the non-affected area. Ficat grade 4 has significantly lower serum and local LncRNA MALAT1 expressions in comparison with grade 3, and Ficat grade 3 showed markedly decreased serum and local LncRNA MALAT1 expressions compared with grade 2. Serum and local LncRNA MALAT1 expressions were significantly and negatively associated with VAS and positively related to the HHS. Further ROC curve analysis indicated that serum MALAT1 may act as a decent indicator in the diagnosis of non-traumatic ONFH. Decreased serum and local MALAT1 expressions may reflect disease severity in non-traumatic ONFH patients.