Human immunodeficiency virus (HIV)-infected patients are routinely being treated with combinations of 3 or 4 drugs (highly active antiretroviral therapy [HAART]), to reduce the risk of viral resistance development. Development of new potent antiretroviral (ARV) drugs is urgently needed to prolong suppression of viral replication in patients infected with HIV. This is a Phase I, open-label trial in healthy women to investigate the pharmacokinetic interaction between the combination of ethinylestradiol and norethindrone and TMC278 25 mg once daily. The trial aims to allow further recommendations regarding the concurrent use of oral contraceptives and TMC278. The trial population will consist of 18 healthy women who are stable on oral contraceptives (OC), specifically ethinylestradiol and norethindrone, or who, if they are not currently using this OC, are willing to start or switch to this OC for the duration of the study.