The flow-induced behavior and Brownian coagulation behavior of a polystyrene latex were studied using a Coulter counter. The coagulation rates in Couette flow (either laminar or Taylor vortex flow), laminar pipe flow, and isotropic turbulent flow were compared with theoretical models. It was shown that the orthokinetic coagulation rate in laminar Couette flow, pipe flow, and isotropic turbulent flow can be described on the basis of existing theory but only when using a lower effective Hamaker constant than predicted from experiments on perikinetic coagulation. This means that the orthokinetic coagulation rate is lower than that predicted by theory. This agrees with measurements performed by other investigators. For Taylor vortex flow, however, the experimental dependence of the stability ratio on the parameter N-SA = 6 pi eta a(3) gamma/A, where a is the particle radius, gamma is the shear rate, and A is a Hamaker constant, is different from that predicted by theory. From experiment and theory it is clear that at equal energy dissipation the coagulation rate is highest for the isotropic turbulent flow.