Peripheral blood specimens and clinical data were obtained over a 12-month period from subjects in the Dubbo Infection Outcomes Study to examine cytokine production in postinfective fatigue syndrome. Ex vivo production of 8 cytokines was examined in 22 case patients and in 42 control subjects who recovered promptly. No significant differences were found. Ongoing production of the cytokines examined does not play a role in postinfective fatigue syndrome.