Recent activities in the field of optical detection on microfluidic chips suggest a variety of applications which can hardly be realised without integrated optical elements on chip. We here present a polydimethylsiloxane (PDMS) microfluidic chip with integrated wave-guides as a high efficient optical detection system for the wavelength range 400-800 nm. The cheap material, the simple fabrication process based on microcasting of polysiloxane and short process times offer the option for a low cost mass production. (c) 2006 Elsevier B.V. All rights reserved.