Twenty novel N-diarylalkenyl-piperidinecarboxylic acid derivatives were synthesized and evaluated as gamma-aminobutyric acid uptake inhibitors. The biological assay showed that (R)-1-[4,4-bis(3-phenoxymethyl-2-thienyl)-3-butenyl]-3-piperidinecarboxylic hydrochloride possessed almost as strong GAT1 inhibitory activity as tiagabine. The synthesis and structure-activity relationships are discussed.