An experimental investigation was conducted to examine the effect of confinement in concrete columns subjected to simulated seismic forces. The experimental program included full-scale tests of reinforced concrete columns with different arrangements of confinement steel. The columns were subjected to constant axial compression and incrementally increasing lateral load reversals. Test results indicate that inelastic response of concrete columns improves very significantly with proper confinement of core concrete. Crossties supporting the longitudinal reinforcement between the corner bars are highly effective in confining the core concrete.