Chemical beam epitaxy has been utilized to demonstrate high efficiency InGaAs/InP tandem solar cells on InP substrates. The key development in achieving such tandems is the growth of high peak current density InGaAs tunnel junctions for use as interconnect between the top and bottom cells. The growth and performance of the InGaAs bottom cell, the InGaAs tunnel junction, and the InP top cell are first independently presented in the paper. Then the growth of an InP-based tandem cell is described followed by a discussion of its performance.