The processive, hand-over-hand mechanism of myosin Va (myoVa) walking on actin has been intensively studied in vitro, but less is known about its behavior within cells. We previously showed that myoVa undergoes a random walk in COS-7 cells as it processively steps along actin tracks within the dense and randomly oriented cortical actin network (Nelson et al. BJ 97:509, 2009). Here we test how the processivity of myoV impacts on the observed cellular motion. A mutant construct with 3-fold shorter run lengths than wild-type myoVa (WT), and one with ∼1.5-fold longer run lengths, were introduced into cultured COS-7 cells by pinocytosis. The motion of Quantum dot (Qdot)-labeled single motors within the cultured cells was analyzed through high resolution TIRF microscopy and single particle tracking. Mean Squared Displacement (MSD) analysis of the motor:Qdot trajectories appear to be diffusive over short time scale (∼1s), and sub-diffusive over longer time scales (∼10s). Strikingly, the diffusion coefficients for the short time scales strictly correlate with the processivity of the motor, and range from 0.06μm2/s for the least processive motor, to 0.15μm2/s for the more processive variant. The non-processive and very slow myoVc, had the lowest diffusion coefficient of any of the constructs tested (0.019μm2/s). The observed diffusion coefficients and the sub-diffusive motion for longer time scales was successfully modeled through Monte Carlo simulations assuming that a processive myoVa motor will either cross over, turn or terminate at actin filament intersections within the randomly oriented actin meshwork. Once the motor terminates its run it undergoes restricted diffusion, being potentially confined within domains that are bounded by cytoskeletal or organellar structures. The motor-dependent cellular behavior supports the idea that the apparently wandering trajectories are random walks by active motors.