As part of a continuing programme investigating the machining of various advanced composite systems, a study has been conducted using a 400 W pulsed Nd-YAG laser to process a glass-ceramic matrix composite comprising SiC fibres in a magnesium-aluminosilicate (MAS) matrix. The trials have been designed to permit a full comparison with results obtained from other ceramic composites, with a view to determining optimum lasing parameters for these and similar composite materials. The tests emphasize the influence of the fibre and matrix phase’s ability to couple with the 1.06 mu m laser emission. The fact that the MAS composition does absorb this energy to some extent, rather than relying entirely on conducted heat from the SiC fibres, has resulted in enhanced material removal rates and improved processed surface quality compared to, for instance, a borosilicate glass matrix material. Whilst the enhancement of either one of these criteria is generally made at the expense of the other, optimum parameters are identified and the resulting surface damage is assessed by electron microscopical examination.