Different type of fibres such as Refrasil (high silica), Kevlar-29, ca
rbon and glass were incorporated in the polyimide matrix for making co
mposites. Cross breaking strengths (CBS) of the composites were determ
ined. Glass fibre-polyimide composites show highest cross bending stre
ngth, 405 MPa. Strength behaviour of composites has been explained on
the basis of bonding between the fibres and the matrix.