Objective: To explore the relationship between TCM Syndrome typing and adrenocortical function in elderly patients with severe sepsis, and to see whether TCM Syndrome Differentiation can provide clinical clues in identifying relative adrenal insufficiency (RAI) in patients with severe sepsis. Methods: Six ty-one old patients with severe sepsis were classified into four types according to TCM Syndrome Differentiation: The severe invasion of toxic-heat type (Type SITH, n = 21 ); the Qi stagnation and blood stasis type ( Type QSBS, n = 11); the sudden depletion of Yang-Qi type ( Type SDYQ, n = 16); and the exhaustion of Qi-Yin type (Type EOQY, n = 13). The base-line level of plasma cortisol in patients of different types and their response to corticotropin stimulation were compared, which were also compared with those of 12 healthy elderly persons synchronously. Results: The base-line level of plasma cortisol was not significantly different between patients of different Syndrome types (P＞0.05), but they were all sgnificantly higher than that in the healthy persons ( P＜0.05). Compared with Type QSBS and Type EOQY, Type SITH and Type SDYQ showed less cortisol concentration increment after corticotropin stimulation ( P＜0.05). RAI was more prevalent in patients of Type SITH and Type SDYQ than in patients of Type QSBS and Type EOQY (57% vs 25 %, P＜0.01). Conclusion: In old patients with severe sepsis, different TCM Syndrome types are associated with different adrenocortical function status. TCM Syndrome differentiation can provide clinical clues in identifying old patients with severe sepsis who have also RAI.