The effect of matrix microstructure on the mechanical properties of carbon fiber felts infiltrated by isothermal chemical vapor infiltration (CVI) has been studied by optical microscopy, scanning electron microscopy and three-point bending tests. The nonbrittle fracture behavior of the investigated composites is related to multiple crack deflections caused by the interfacial sliding between pyrocarbon layers with a varying texture degree and the delamination microcracking within the highly textured pyrocarbon layer. An increase of the flexural strength is observed by the composite having a multilayered pyrocarbon matrix. (C) 2002 Elsevier Science B.V. All rights reserved.