Many countries with financial support for HIV treatment experience delays in scale-up because of bureaucratic, operational, and technical obstacles. The authors describe the Peruvian National HIV Program's response to such challenges. A team of consultants experienced in the scale-up of the Peruvian national program to treat multidrug-resistant tuberculosis worked with the national HIV program to identify and address key factors contributing to slow enrollment of HIV patients into the antiretroviral treatment program. The rate of enrollment into the antiretroviral treatment program increased from 124 patients/month in the first 9 months of the program to 226 patients/month in the last 7 months, an increase of 83%. This strategy achieved 38.5% coverage of the population in need. Effective programmatic expansion of the Peruvian National HIV Program was facilitated by a multidisciplinary collaboration in a systematized effort to overcome barriers to scale-up. © 2006 Sage Publications.