We present a design for wave guides in three-dimensional photonic crystals. A single-mode three-dimensional photonic crystal waveguide can be created in the stacked-stripe structure by removing one stripe. A method for creating a waveguide bend is described. Numerical simulations show that a transmittance of more than 95% can be obtained over a wide range of frequencies. The results suggest that various types of optical circuits, such as a T-branch waveguide, can be created by removing or adding stripes in the stacked-stripe structure.