In recent years, the United States Congress introduced several competing bills that would establish an abbreviated approval process for “follow-on” biological drug products, or therapeutically similar versions of “reference” biologics that have already been approved for human use. This proposed abbreviated approval process would in some ways resemble the abbreviated new drug application (ANDA) process established under the 1984 Hatch-Waxman Act for the approval of generic small-molecule drugs. Unlike generic small-molecule drugs, however, follow-on biologics are more difficult than generic small-molecule drugs for regulatory agencies to evaluate and approve, because their inherent variability prevents them from being precisely equivalent to their reference counterparts. While none of these bills has yet passed, they nevertheless provide insight into the regulatory approaches that Congress is considering, and may eventually adopt, for the approval of follow-on biologics. This article summarizes some of the salient features of these bills.