In this study, 100% viscose yarns were spun at different delivery speed and nozzle air pressure values (within a range of 300-450 m/min and 0.46-0.58 MPa, respectively) by using Murata Vortex spinning system (MVS). Then, the effect of these parameters on physical properties of yarns (such as irregularity, hairiness, tensile strength, breaking elongation, yarn density and diameter) was analysed comparing with the results given in literature for various fiber types. The results show that yarn delivery speed and nozzle air pressure have no effect on yarn irregularity, while they affect hairiness, breaking elongation, diameter and density of yarns. On the other hand, an increase in nozzle air pressure has a slight effect on yarn tenacity while ...