Objective To discuss the clinical value of procalcitonin (PCT) in guiding antibiotics use in children with severe diseases. Methods The clinical data of patients admitted to intensive care unit from January 2012 to July 2012 were retrospectively analyzed. The patients without antibiotics use before admission and with procalcitonin level less than 0.5 ng/ml on admission were selected. The body temperature, infection indicators and prognosis were compared between patients with and without antibiotics use during hospitalization. Results There was no difference in body temperature, PCT, C-reactive pro-tein (CRP), erythrocyte sedimentation rate (ESR) and white blood cell count (WBC) on admission between patients with and without antibiotics use during hospitalization. The PCT level was increased signiifcantly (P<0.05) on the day of starting the an-tibiotics when compared with that on admission in 60 patients while there was no change in the levels of WBC and CRP. Com-pared with the day of starting the antibiotics, body temperature declined (P<0.05) and PCT level in 56 patients reexamined was decreased (P<0.05) at 3 days after antibiotics use. Two hundred and eleven patients (98.14%) had favorable prognosis. Conclu-sions Monitoring PCT can guiding the clinical use of antibiotics.