In this study the effects of two welding positions included in flat and upward vertical on the mechanical properties and microstructure of high strength weld metal deposited with shielded metal arc welding (SMAW) using an electrode of ASME SFA 5.5-96 E9018B3 type have been investigated. The aim of the present work is to study the effects of these two welding positions for a weld metal alloyed with 1%Mo, 2%Cr, 0.79%Mn, and 0.08% C in the stress relieved condition. For studying mechanical properties Tensile, Impact and hardness experiments have been conducted; meanwhile chemical analysis and microstructure studying have been carried out on specimens. The results show that welding position does not have any significant effect on tensile and hardness of the weld metal but in vertical position welding metal toughness is lower than toughness in flat position in all temperatures. Transition temperature of ductile fracture to brittle fracture is -50 °C for E9018B3 in welding of high strength micro alloyed steels.