Objective: To study the clinical characteristics and prognosis of patients with persistent inflammation immunosuppression and catabolism syndrome (PICS) in ICU. Methods: A total of 126 patients admitted to ICU (ICU stay of more than 10 days, age≥18 years) between January 2014 to December 2014 were retrospectively studied.Data were collected from electronic medical records including demographics, underlying disease, Acute Physiology and Chronic Health Evaluation Ⅱ (APACHEⅡ) score, Sequential Organ Failure Assessment (SOFA) score, laboratory parameters, ICU acquired infections and clinical outcome. Results: The overall incidence of PICS in ICU patients (ICU stay of more than 10 days) was 50.0%(63/126). There were no significant differences in baseline data such as gender, age, APACHEⅡscore, SOFA score and underlying diseases between the two groups(all P>0.05). Compared with the non-PICS group, there were more patients with gastrointestinal perforation in the PICS group (P=0.042), however, the medical or surgical admission did not differ between the two groups(P>0.05). During the stay in ICU, the PICS group showed a higher risk of developing acquired infections compared with the non-PICS group[PICS 63.5%(40/63) vs non-PICS 23.8%(15/63); P<0.001]. The infections were more caused by Candida in the PICS group than the non-PICS group [PICS 22.4%(11/49) vs non-PICS 2/17; P=0.003]. Moreover, the PICS group experienced longer stay in ICU[PICS(31.6±28.8) days vs non-PICS (20.4±11.3) days; P=0.0046] and higher ICU mortality [PICS 28.6%(18/63) vs non-PICS 6.3%(4/63), P=0.001]. Conclusion: PICS is a common manifestation of patients who stay in ICU more than 10 days, which is associated with high risk of ICU acquired infections, prolonged length of stay and high mortality.