The objective of this study is to analyze the flow pattern trough a patient specific lower airway under multiple breathing conditions. The measured Particle Image Velocimetry (PIV) results are quantitatively and quantitatively compared to Computational Fluid Dynamics (CFD) simulations. A patient specific 3D model of the lower airway geometry down to the 3rd generation was created to investigate the stationary and oscillatory flow through the branching network by PIV. A water/glycerin mixture with the same refractive index as the transparent silicone model was created and spherical particles were used as tracer particles. The mass flow rate and frequency were adjusted to the properties of the fluid mixture. In this paper, a first comparison was made between the PIV and CFD results of stationary and oscillatory flows for peak inspiration and expiration for a constant Reynolds number and Womersley number. Immediately one can see the different nature of the flow in inspiration and expiration. The comparison between the stationary flows showed that at inspiration the velocity profile has a more constant velocity distribution in PIV than in CFD. The difference in velocity profile lowers for an oscillating flow analysis. At maximum expiration the PIV and CFD results show the two peak velocity profile for a stationary flow while at oscillating flow conditions the flow of the right main bronchus prevails.