This randomized behavioral trial examined whether youth living with HIV (YLH) receiving cell-phone support with study funded phone plans, demonstrated improved adherence and viral control during the 24 week intervention and 24 weeks post-intervention compared to controls. Monday through Friday phone calls confirmed medications were taken, provided problem-solving support, and referred to services to address adherence barriers. Of 37 participants (ages 15–24), 62 % were male and 70 % were African American. Self-reported adherence was significantly higher in the intervention group compared to the control at 24 and 48 weeks for the past month (P = 0.007) and log 10 HIV VL was significantly lower at both 24 weeks (2.82 versus 4.52 P = 0.002) and 48 weeks (3.23 versus 4.23 P = 0.043). Adherence and viral load showed medium to large effect sizes across the 48 week study. This is the first study to demonstrate sustained clinically significant reductions in HIV VL using youth friendly technology.