Single-phase air flow periodically developed at constant property (Pr=0.7), laminar forced convection in two-dimensional sinusoidal corrugated-plate channels, which are maintained at uniform wall temperature are considered. The governing differential equations for continuity, momentum, and energy equations are solved computationally using finite-volume technique, where the pressure term is handled by the SIMPLE algorithm. The computational grid is non-orthogonal and non-uniform, and it is generated algebraically. All the dependent variables are stored in a non-staggered manner. For the two-dimensional problem, numerical solutions are obtained for a wide range of channel corrugation aspect ratios (0.25 ≤ γ ≤ 1.0), plate spacing ratio (0.25 ≤ ε ≤ 1.5), and flow rates (10 ≤ Re ≤ 1000). The flow field is found to be strongly influenced by γ, ε and Re, and it displays two distinct regimes: a low Re or γ, ε undisturbed laminar-flow regime, and a high Re or γ, ε swirl-flow regime. In the no-swirl regime, the flow behavior is very similar to that in fully developed straight-duct flows with no cross-stream disturbance. In the swirl regime, flow separation and reattachment in the corrugation troughs generates transverse vortex cells that grow spatially with Re, γ and ε, and the transition to this regime also depends on Re, ε and γ. The mixing produced by these self-sustained transverse vortices is found to significantly enhance the heat transfer, depending upon Re, γ and ε, with a relatively small friction factor penalty.