An analysis is made of steady laminar flow in pipes with axially symmetric and non-symmetric wavy walls. Secondary flow patterns and friction factors are obtained for the case of small amplitude waviness. When kRe (k: the pipe wall wave number, Re: Reynolds number) is large, the adaptation of wall waviness to secondary flow is delayed due to the inertia forces of fluid and comes to be confined to a region near the pipe wall. When k is small, the friction factors depend on β, the number of helix starts, but not on Re. When k is large, on the contrary, they are almost independent of β.