We demonstrate that the biological effect of an oligonucleotide is influenced by its route of cellular uptake. Utilizing a splice-switching antisense oligonucleotide (SSO) and a sensitive reporter assay involving correction of RNA splicing, we examined induction of luciferase in cells treated either with various concentrations of an unconjugated ("free") SSO or an SSO conjugated to a bivalent RGD ligand that promotes binding to the alphavbeta3 integrin (RGD-SSO). Under conditions of equal accumulation in cells, the RGD-SSO consistently had a greater effect on luciferase induction than the unconjugated SSO. We determined that the RGD-SSO and the unconjugated SSO were internalized by distinct endocytotic pathways, suggesting that the route of internalization affects the magnitude of the biological response.