The use of high-tensile-strength steel and deformed bars for reinforcing bars is an incressing tendency. The former increases the working stresses considerably, accordingly decreasing the required amount of reinforcement. The latter, generally,eliminates the need for end hooks, which results in an equivalent economical effect as the former. On the use of them, however, lacks of an exact understanding of the behavior of cracking may results in reinforced concrete members should be carefully considered, no matter they may be tensile or flexural cracks. Unfortunately in this field, the standard procedures or specifications for evaluation or limitation of cracking in reinforced concrete members have not yet been established except in few countries. To expect the economical and perfect use of high-tensile-strength steel or deformed bars, it is considered of urgent need to establish them through extensive theoretical and experimental studies and comprehensive field investigations.