In this study, commercially pure (CP) titanium sheets (ASTM Grade 2) were welded by resistance spot welding at different welding parameters and under different welding environments. The welded joints were subjected to tensile-shearing tests in order to determine the strength of the welded zones. In addition, hardness and micro structural examinations were carried out in order to examine the influence of welding parameters on the welded joints. The results showed that increasing current time and electrode force increased the tensile shearing strength and the joints obtained tinder the argon atmosphere gave better ten site-shearing strength. Hardness measurement results indicated that welding nugget gave the highest hardness and the heat affected zone (HAZ) and the base metal followed this. The argon gas used during the welding process was seen to have no influence on the hardness values. Microstructural examinations revealed that the deformations took place in the welding zone during welding. The twinning took place in the grains. High electrode force and high weld cycles, were used during the welding, increased the twinning. (c) 2005 Elsevier Ltd. All rights reserved.