AIMSLow rifampicin plasma concentrations can lead to treatment failure and increased risk of developing drug resistant tuberculosis. The objectives of this study were to characterize the population pharmacokinetics (popPK) of rifampicin in Malawian children and adults with tuberculosis, simulate exposures under revised WHO dosing guidelines that aim to reduce the risk of low exposures of rifampicin and examine predicted exposures using weight-and agebased dosing bands under new dosing recommendations. METHODSPatients were recruited at least two weeks after initiation of the intensive phase of treatment and received RIF in FDC of anti-TB drugs. A total of 5-6 rich and 1-2 sparse samples were collected. NONMEM (v7.2) was used to build a population-PK model.