Aim: The aim of the study was to determine antimicrobial usage in paediatric intensive care units (PICUs) in China. Methods: Data were equally collected from 540 charts of PICUs in the three Chinese tertiary teaching children hospitals in 2006. The data included demographic, clinical data and those on antimicrobial usage and results of microbiological examinations. Results: Of the 540 cases, 524 (94.7%) patients received at least one antimicrobial agent. The main treatment started empirically in 387 (71.6%). The third-generation cephalosporins were the major antimicrobials used in all participating hospitals, accounting for 227 (31%). Bacteria were isolated from 48%, 68% and 59% of the three PICUs. Six common pathogens accounted for more than 75% of the isolated bacteria. The rates of Escherichia coli isolates resistant to cefotaxime were 73.8%, 58.3% and 49.2%, respectively, with the rate being higher in H1 than in H2 and H3 (both p < 0.01). Conclusions: Irrational use of antimicrobials exists in clinical practice of PICUs in China. It is recommended that antimicrobial usage should be guided by bacterial isolation and antimicrobial susceptibility tests in order to select correct antimicrobials and to prevent emergency of drug-resistant strains in PICUs.