Wuchereria bancrofti microfilarial antigen was investigated in skin test on: (1) Microfilaria carriers, (2) Amicrofilaraemic cases from endemic villages with and without intestinal helminths, (3) Cases having apparent symptoms and signs of filariasis. The anti-gen reacted with specificity in cases having apparent symptoms and signs of filariasis. In microfilaria carriers and amicrofilaraemic individuals from endemic areas no reaction was seen. The diag-nostic value o f W. bancrofti microflarial antigen in chronic cases has been discussed.