We present a novel microfabrication approach to create microflow cytometers. Femtosecond laser pulses are used in a direct-write embodiment to create, from fused silica monoliths, extremely robust flow cytometers with uncommon characteristics. One of the most interesting features associated with the femtosecond direct-write approach is the opportunity to fabricate optical and microfluidic elements in a single continuous step. This capability affects the design and performance of microflow cytometers in many ways. We expect that the direct-write process will create opportunities to expand the use of microflow cytometers outside traditional markets.