Abstract: A portable bridge structure includes a pair of releasably connectable stair and platform assemblies which form opposite ends of the bridge structure. Each assembly includes several components which are movable between folded and erected positions. When all the components are in their folded positions, each assembly forms a flat, compact bundle to facilitate transport and storage of the bridge structure. The components of each assembly include pivotally interconnected stair and platform sections and bracing means for retaining the sections in erected positions at selected angles of relative inclination. In preferred practice, each assembly also includes foldable stabilizer and railing structures carried respectively on the stair and platform sections.