The Havana trial, a randomized, prospective study, demonstrated that expert interpretation of genotypic resistance test (GRT) results improved virological outcomes in human immunodeficiency virus type 1 (HIV-1)-infected patients for whom highly active antiretroviral therapy (HAART) was failing. The impact of expert advice in routine clinical practice is unknown. We retrospectively evaluated the virological outcomes of 74 patients for whom HAART was failing and whose clinical providers accepted or rejected HAART regimens recommended by an expert panel who routinely reviewed GRT results. Fifty (68%) of 74 patients received regimens recommended by the expert panel ("advice accepted" [AA]), and 24 patients (32%) received regimens per the clinician's preference ("advice rejected" [AR]). After 24 weeks, AA and AR groups had median decreases in the plasma HIV-1 RNA viral load of 2.6 and 1.3 log(10) copies/mL, respectively (P=.0001). Twenty-six (52%) of 50 patients in the AA group and 5 (21%) of 24 patients in the AR group had a plasma HIV-1 RNA viral load of <50 copies/mL (P=.01). Consideration should be given to enlisting expert assistance in the interpretation of GRT results in routine clinical practice.