The present invention relates to 2′-chloroacetylenyl-substituted nucleoside derivatives of the general formula (I):As well as pharmaceutical compositions comprising such compounds and methods to treat or prevent an HIV infection, HBV infection, HCV infection or abnormal cellular proliferation, comprising administering said compounds or compositions. In addition, the present invention includes processes for the preparation of such compounds, and the related β-D and β-L-nucleoside derivatives.