High strength ceramic composites, reinforced with Si-N and Si-B-O-N ceramic fibres, were prepared by the preceramic polymer impregnation method. Low-viscosity polysilazanes with a 70-90 wt% ceramic yield, were used as a matrix precursor. To obtain dense composites, the impregnation, curing and firing processes were repeated. Three-point flexural strength of the UD and 2D (cross-ply) ceramic fibre reinforced ceramic composites were shown to be as high as 1000 and 600 MPa, respectively. This resulted from the dense silicon nitride matrix and controlled fibre/matrix interface.