Theory of Computing ------------------- Title : Improved Inapproximability for TSP Authors : Michael Lampis Volume : 10 Number : 9 Pages : 217-236 URL : https://theoryofcomputing.org/articles/v010a009 Abstract -------- The Traveling Salesman Problem is one of the most studied problems in the theory of algorithms and its approximability is a long-standing open question. Prior to the present work, the best known inapproximability threshold was 220/219, due to Papadimitriou and Vempala. Here, using an essentially different construction and also relying on the work of Berman and Karpinski on bounded-occurrence CSPs, we give an alternative and simpler inapproximability proof which improves the bound to 185/184. A conference version of this paper appeared in the Proceedings of the 15th International Workshop on Approximation Algorithms for Combinatorial Optimization Problems (APPROX'2012).