Studies on the serum concentrations of micronutrients in tuberculosis (TB), and their relationship to the acute-phase response (APR), are scarce. The serum concentrations of zinc, copper, selenium and vitamins A and E in 46 smear-positive cases of pulmonary TB (PTB) from Ecuador were therefore compared with those in 10 healthy Ecuadorian volunteers, and the correlations between these concentrations and the serum concentration of C-reactive protein (CRP) were evaluated. Compared with the healthy volunteers, the PTB cases had significantly lower serum concentrations of zinc, retinol and selenium and significantly higher serum concentrations of copper. Both groups had moderately high concentrations of selenium in their sera. The PTB cases who had >50 mg CRP/ litre (a concentration indicative of an APR) had lower serum concentrations of retinol and zinc than the cases with lower CRP concentrations. In patients with PTB, hypozincaemia and hyporetinolaemia are strongly associated with the APR. It is therefore necessary to consider the extent of activation of the APR when interpreting serum micronutrient concentrations in patients with TB.