Objective To explore the clinical significance of serum ProGRP in diagnosis of SCLC.Methods Serum ProGRP were detected in twenty-three SCLC patients,forty NSCLC patients and forty-three patients with benign pulmonary disease whose were definite diagnosis collected from April 15,2016 to July 19,2016,and a contemporary cohort of 40 healthy controls were while recruited.Results The levels of ProGRP in SCLC group were significantly higher than those in NSCLC group,benign pulmonary disease group and healthy control group(P <0.05).The levels of ProGRP in extensive disease group were significantly higher than those in 1imited disease group(P <0.05).There was no significant difference in the positive rates of ProGRP between the sex group and age group (P > 0.05 ).The boundary value of diagnosis of SCLC through ProGRP identified through ROC curve was 65.66 ng/L.The sensitivity and specificity of the ProGRP for the diagnosis of SCLC were respectively 90.9% and 89.9%.Conclu-sion Serum ProGRP can be use as a sensitive and specific index for diagnosis of SCLC,and the level of ProGRP can also be used for the clinical staging of SCLC.