The secretion of adipocytokines is influenced by fat mass, but also by various situations related to acute stress (food deprivation, or critical state related to inflamatory or infectious syndromes). Adipocytokinic secretory profile could be therefore used for the diagnosis of the type of critical state, as well for the evolution and survival prognosis of patients. The modifications of adipocytokinic markers during the first hours after surgical intervention are insufficiently described. We characterised for the first time the precocious dynamics of leptin comparated to classical inflammation markers (C-reactive protein and interleukin 6 (IL6)) during the systemic inflammatory response syndrome (SIRS) or sepsis at patients submitted to surgical intervention. Our prospective study included three groups of 20 patients the SIRS group (SI) with major elective abdominal surgery, the sepsis group (SE) witn communitary intraabdominal infections and the control group (C). Leptin, C-reactive protein, an IL6 were measured at 0 point in all three groups and then serially for 5 days after surgery. We observed that leptin values increase precociously at 1224 h in group SI (P<0.05), but remain within the normal range in the SE group. The patients from the SE group had a higher survival rate when they had higher leptin (>6 ng/ml) and lower IL6 levels (<150 pg/ml) within the first 24 h. The prognosis was worsened at patients having low leptin and increased IL6 at this time. Leptin has, therefore, a different precocious dynamics in SIRS than in sepsis patients.Early measurement of leptin levels, together with other inflammatory markers, may be useful for the differential diagnosis and prognosis of surgical critical patients.