A flow injection hydride generation atomic absorption spectrometric (FI-HGAAS) method was developed for the determination of thallium at the ng mL-1 levels. Palladium, an effective enhancement reagent, was added to the acidified sample solution. The presence of micro amounts of Rhodamine B increased the hydride generation efficiency further. The acidified sample solution containing palladium and Rhodamine B merged with the aqueous sodium tetrahydroborate solution at room temperature. The generated gaseous phase was separated in a gasexpanded gas-liquid separator and was led directly into a quartz tube atomizer at 1000℃ via the Ar carrier gas for detection by AAS.