Obsessive-compulsive disorder (OCD) is a chronic and refractory mental disorder with early onset, low response rate, and poor prognosis. Studies have shown that the age of onset, severity, course of disease, and untreated course of disease may affect its clinical efficacy. At present, there are few studies on the duration of untreated illness (DUI) of OCD patients. The current medical status and untreated course of OCD patients in China are still unclear. This study aims to investigate the current medical status of OCD patients in psychiatric outpatients of a general hospital, including the course of disease and DUI as well as its influencing factors. A total of 310 outpatients with OCD who visited the Department of Mental Health, Guangdong Provincial People's Hospital for the first time, were recruited and interviewed. The information including age, gender, years of education, marital status, work status, age of onset, comorbid mental disorders, age of first treatment, course of disease, and DUI were collected. We also calculated the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and Global Assessment Function (GAF) scores for total sample to analyze the demographic characteristics and clinical data of patients with OCT. The median DUI was used as the cut-off value, and the patients were divided into a short DUI group and a long DUI group. The differences in demographic characteristics and clinical data between the 2 groups were compared, and the factors affecting the DUI were analyzed. There were 158 males (51%) and 152 females (49%). The age of onset was (19.48±7.97) years. The years of education were 13.49±3.13; 215 (69.4%) were single and 95 (30.6%) were married; 103 (33.2%) were employed and 207 (66.8%) were unemployed. The median course of OCD was 4 years and the median DUI was 3 years. There were 177 cases in the short DUI (≤3 years) group and 133 cases in the long DUI (>3 years) group. Compared with the long DUI group, the patients in the short DUI group were younger (P<0.01); they had mild obsessive-compulsive symptoms (P<0.05) and a shorter education period and course of disease (P<0.01 and P<0.001, respectively); and they were more unemployed and single (both P<0.001). Correlation analysis showed that DUI was positively correlated with age, course of disease, years of education, and Y-BOCS score (r=0.45, P<0.001; r=0.74, P<0.001; r=0.27, P<0.001; r=0.17, P<0.01). When the DUI of OCD patients was used as the dependent variable, Y-BOCS, age, course of disease, whether to work, marital status, and years of education were used as the independent variables for binary logistic regression analysis, which showed that the duration of illness could predict the short and long DUI of OCD [Wald χ2=49.78, Exp(B)=1.34, P<0.001]. Investigation for the medical status of OCD patients in the psychiatric outpatients of a general hospital in Guangdong, China shows that the duration of illness of OCD patients in the psychiatric outpatients and the DUI of OCD patients are generally shorter than previous foreign reports. The DUI of OCD patients is affected by the course of disease, age, severity of symptoms, and other factors. In the future, large sample, multi-center, and follow-up studies could be considered to further explore the influencing factors for the DUI of OCD and the impact on the prognosis of the disease, to help improve the status of delayed treatment for OCD and improve the effective rate of OCD treatment.