A developing laminar flow of power-law fluids in the entrance region of curved pipes has been investigated by analyzing the three-dimensional elliptic equation numerically and measuring velocity profile with an optical fiber LDV. The flow mechanism from the curved pipe inlet to the fully-developed region has been made clear under the condition of the power index n> 0.6, two curvature ratios Rc=10 and 30, and Dean number De=100500. As the power index decreases, the primary flow becomes more highly distorted and the axial velocity profile with double peaks appears on the symmetry plane in the initial development. Also, the secondary flow grows drastically at the inlet adjacency and declines rapidly to form another vortex pair in a part of developing region.