Deep wells containing H2S necessitates drill strings that combine high strength and Sulfide Stress Cracking (SSC) resistance. Conventional API 5D drill pipe and API Spec7 tool joints do not meet these requirements. This paper is aimed at evaluating the performances of new 95 ksi grade and new 105 ksi grade drill pipes for sour service. Mechanical properties and SSC resistance have been investigated on both pipes, tools and weld areas. Optimized chemical composition, manufacturing process and heat treatment are pointed out. Key words : SSC, sour service, drill pipe, high strength, H2S, pipe body, tube upset, tool joints.