The problem of determining the distribution of stresses and the deformations of an orthotropic strip, damaged by a crack normal to the edges of the strip, is investigated. The strip is deformed by pressure applied to the faces of the crack. Two types of boundary conditions are considered: (i) the boundary of the strip is stress free, (ii) the strip is confined between two rigid planes. The mixed boundary conditions lead to dual integral equations, which are in each case reduced to a Fredholm equation of the second kind. These equations are finally solved by the use of the Gaussian quadrature formula. Stress intensity factor, deformation on the crack surface, the strain energy required to open the crack and the critical pressure required for spreading of the crack are calculated for different values of b/a and the effect of orthotropy is shown.