This paper reports an experimental study of transverse cracking in 90 plies of ( /902)s laminates of graphite/epoxy. The constraint to this cracking process is varied by varying the angle to have the discrete values of 0, 15, 30 and 40. The evolution of crack density and the associated stiffness changes of the laminates are studied. The crack densities are measured in tensile specimens at increasing stress levels by examining the edge replicas under an optical microscope and the continuity of these cracks between the specimen edges is ascertained by X-ray radiography. The stiffness changes are reported here and the stiffness-damage relationships are analyzed in a separate study.