Abstract: Periodic parallel cracks in an infinite medium underfar-field inplane tensile stress are investigated. By using thesingular analysis of the complex stress function at the concentrated loadpoint and the tips of cracks, as well as combining periodicity of thehyperbolic function, a closed form solution of the stress intensity factorto the problem is obtained. A comparison of the present solution withexisting numerical results, shows a good agreement. The presentexact solution can be used to study the interaction ofmulti-cracks and the structural integrity assessment.