Passive alignment of semiconductor lasers and singlemode fibres has been achieved for the first time using a micromachined silicon subtrate. Mechanical alignment features fabricated on the substrate surface were used to align the active regions of an InGaAsP/InP laser array to four single-mode fibres held in V grooves. Optical coupling efficiencies have been achieved that are comparable to values obtained using the conventional technique of active fibre manipulation. The approach, called silicon waferboard, offers the potential for low-cost optoelectronic device packaging as well as a means for dense hybrid integration of optoelectronic, electronic and optical components required for multifibre, multichip systems.