In this study, we examined the variability in rifampicin Cmax and AUC0–7 in Ethiopian TB patients in relation to the recommended target concentration for optimal therapeutic efficacy and the impact of common functional genetic variants in SLCO1B1 (rs2306283 and rs4149056), ABCB1 (rs1045642 and rs3842), CES 2 (rs4783745) and AADAC (rs1803155) on between-patient variability in rifampicin plasma concentration. The gene discussed is SLCO1B1; the disease is tuberculosis.