Intralaminar cracking in plies of composite laminates is the first microdamage mode that affects thermo-elastic properties and may trigger local delaminations and final failure of the composite. Intralaminar cracks are like tunnels running along the fiber direction in the ply. The number of cracks increases with the increase of the applied load or with the number of cycles in fatigue loading. In this article, the cracking evolution is analyzed distinguishing two phases in development: initiation and propagation. For laminates with thick plies, the initiation ends with triggering sudden propagation and, therefore, concept of statistical initiation stress distribution in the ply together with Monte Carlo method is used for analysis. For thin-ply laminates, crack initiation does not lead to immediate propagation and the energy release concept is used to analyze crack propagation.