Device activation after cochlear implant surgery was typically performed after wound healing, and varies anytime from three to four weeks after surgery. Nowadays, activation is performed as early as two to three days after surgery. The authors evaluated the effect of early activation (less than 15 days) compared to device activation after three to six weeks (control group) after cochlear implantation in patients with substantial residual low-frequency hearing loss. The study results showed that there was a decrease in the postoperative low-frequency hearing compared to the preoperative in the study group as well as the control group. During the first year after implantation, there was no statistically significant difference in the speech recognition in quiet and in noise for both groups. The study results suggest that early activation is not only feasible but does not influence postoperative hearing preservation.