The invention provides a microfluidic system for monitoring the condition of lubricating oil. The microfluidic system comprises a microfluidic device with at least one microchannel (40) configured to allow a sample of lubricating oil (52a) to pass therethrough as a laminar flow. The device has at least one separating device (41) configured to selectively separate at least one component (54b) from the lubricating oil (52a) in the fluid flow. The microfluidic system also comprises a detector device (20, 22) configured to detect the presence and/or measure at least one property of the at least one component passing through the microfluidic device after separation in the microchannel (40).