The purpose of this R01 proposal is to evaluate the clinical impact, hypothesized mechanisms of behavior change, and cost-effectiveness of a partners-focused integrated elimination of mother-to-child transmission of HIV (EMTCT) package comprised of: 1) antenatal care-based couples HIV testing, ART enrollment, and care for sero-concordant HIV+ expectant couples; (2) Couples-based treatment in the post-partum period; (3) Couple-based education and skills building; and (4) Treatment continuity with the support of expert-patient (peer) supporters from couples who have successfully navigated EMTCT. This innovative approach to scaling up EMTCT services, if proven feasible and effective, will be adopted in President's Emergency Plan for AIDS Relief (PEPFAR) programs to accelerate progress toward EMTCT and helping families with HIV infection live long, healthy lives.