The design and evaluation of a 3-dimensional FPGA architecture called Rothko will be described. Rothko takes advantage of a novel 3-dimensional VLSI circuit technology developed at Northeastern University that is based on transferred circuits with interconnections between layers of circuits. The Rothko 3-D FPGA architecture is based on a sea-of-gates FPGA model first proposed in the Triptych architecture (a 2-D architecture) in which individual cells have the dual functions of routing and logic implementation. Our 3-D VLSI technology allows metal interconnections to be made between cells on different layers so that Rothko is truly 3-D. A very fine-grain interconnection scheme is provided with each cell connected to the one above/below it. In this paper we present the architectural design of this 3-D FPGA. The 3-D technology that supports the Rothko architecture is also described. An example of mapping a combinational multiplier to both the Rothko and Triptych architectures is provided to demonstrate the advantages of Rothko.