This paper presents rheological investigations of pigmented and non-pigmented powder coatings with the oscillation technique. The measured viscosity-temperature behaviour of the powder coatings exhibits a characteristic viscosity minimum which strongly depends on the selected heating rate. Here, the viscosity level decreases as the heating rate increases, while the temperature at which the minimum occurs is shifted to higher temperature values. The rheological results are compared with surface structure measurements of the final powder coating film. We found that the long waviness of the surface increases at higher viscosity levels.