To assess diurnal profiles of impulse-oscillometry (IOS) changes of IOS-parameters between different body positions have been studied using a special set IOS-Bedside for individual home care. IOS has been applied in lateral lying and in sitting position in 20 healthy female and male probands, aged 10-67, during 24 hours in intervals of 3 hours. In each test during normal breathing for approximately 30 sec about 130 spectral and structural analyses have been performed at an impulse distance of 0.2 sec. The global means of resistance at 5 Hz (R5) in lying position are in men about 0.6 and in women about 0.3 hPa/l/s higher than in sitting position, those of reactance in men and women are only about 0.2 hPa/l/s lower. There is a distinct diurnal periodicity of the differences. The maxima of them may occur at different hours of the day in single probands; but at the average mean the maxima are found at the end of night. The differences of oscillation parameters between lying and sitting position are bigger at end-expiration than at end-inspiration. The resistance-flow-gradients, representing the component of turbulent flow, are enlarged in lying position especially at night.