Patients receive a treatment regimen of adefovir dipivoxil, didanosine, efavirenz, and lamivudine for 48 weeks. During the study, patients are evaluated for changes from baseline in plasma HIV-1 RNA and lymphocyte subsets and for the development of adverse experiences and laboratory toxicities. At Weeks 8, 12, 24, and 48, patients are assessed for adherence to study treatment with a questionnaire. Patients who experience virologic failure are discontinued from the study. Patients who experience treatment intolerance may have their antiretroviral treatment regimens changed. After Week 48, patients with documented virologic response are eligible to continue receiving study treatment.