Ntcheu district hospital, Malawi.To assess a screening strategy for tuberculosis (TB) suspects using two sputum smears.A strategy of screening all TB suspects with two sputum smears for 6 months (1 July-31 December 1998) was compared with the period 1 January to 30 June 1998 during which the strategy of screening TB suspects with three sputum smears was in use. All chest radiographs of patients with negative sputum smears were assessed, and in those with pulmonary cavities and extensive disease a third sputum smear was examined. Data were collected from the laboratory sputum register and the TB register. The two 6-month periods were compared.In the laboratory register, using a two-sputum strategy, 186 (16%) of 1152 TB suspects were smear-positive, a result that was no different than when the three-sputum strategy was used, where 173 (16%) of 1106 TB suspects were smear-positive. The clinical pattern of TB using the different screening strategies was similar, with 58% of registered patients smear-positive with the two-sputum strategy and 54% smear-positive with the three-sputum strategy. In the first 6 months 3177 sputum smears were examined compared to 2266 smears in the second 6 months, a 29% reduction in the number of smears examined. The cost of consumables using the strategy of three sputum smears was USD $731 compared with USD $521 using the strategy of two sputum smears. C O N C L U S I O N S: Screening TB suspects using two sputum smears is as effective as screening using three sputum smears, and is associated with less laboratory work and savings in costs.