Dioxin is one of the most toxic chemicals and susbtainable in the environernent. During the Vietnam - America war, these toxic chemicals were sprayed in some areas of South Vietnam by U.S military. Dioxin cause consequences to human health and environment in Vietnam for many years ago and it continues to do so for long time. The authors studied the effects of di'oxin on steroid hormone in saliva and serum of lactacting women (aged 20 to 30) living in hot-spot area and nonexposed area. The results showed that, cortisol and cortisone concentrations in serum and saliva of the women in hot-spot area are higher than those in non-exposed area (p 0.001). There was no difference between DHEA and Andosteindion hormone levels in two areas (p 0.05). There was positive correlation between cortisol and cortisol hormone levels in serum and in saliva with PCDD, PCDF, and PCDD + PCDF in both areas, with statistical significance p 0.01.