Background Little is known about the demographic and clinical differences between early- and late-onset depressions (EOD and LOD, respectively) in Chinese patients. This study examined the demographic and clinical profile of EOD (<=25 years) compared to LOD (>25 years) in China. Methods A consecutively recruited sample of 1178 patients with MDD was assessed in 13 psychiatric hospitals or psychiatric units of general hospitals in China nationwide. The cross-sectional data of patients demographic and clinical characteristics and prescriptions of psychotropic drugs including antidepressants, mood stabilizers, antipsychotics and benzodiazepines were recorded using a standardized protocol and data collection procedure. Results Two hundred and seventy five (23.3%) of the 1178 patients fulfilled criteria for EOD. In multiple logistic regression analyses, compared to LOD patients their EOD counterparts were more likely to be unmarried and unemployed, had more atypical and psychotic depressive episodes, had bipolar features, while they had more lifetime depressive episodes. Conclusions The demographic and more severe clinical features of EOD in Chinese patients were basically consistent with those found in Western populations. The association between socio-cultural factors and development of EOD warrants further studies.