Abstract— This paper presents a post-route, timingconstrained gate-sizing algorithm for crosstalk reduction. Gate-sizing has emerged as a practical and feasible method to reduce crosstalk in deep sub-micron VLSI circuits. It is however critical to ensure that the timing constraints of the circuit are not violated after sizing. We present an iterative gatesizing algorithm for crosstalk reduction based on Lagrangian Relaxation that optimizes area and power while ensuring that the given timing constraints are met. Experimental results demonstrating the effectiveness of the algorithm are reported for the ISCAS benchmarks and other large circuits with comparisons to an alternative design methodology.