Abstract: A respiratory exerciser particularly for encouraging deeper inhalation by post-surgical patients. The exerciser includes a transparent cylinder that is adapted to be supported in a vertical position. A lightweight ball is positioned in the cylinder which is provided with closure members at its upper and lower ends. The closure member for the upper end of the cylinder has a pair of apertures therethrough, and an open-ended tube is slidably mounted in one of the apertures so that it projects down into the cylinder. A flexible inhalation tube is connected to the other closure member aperture and by inhaling air through this tube the patient can cause the ball to rise in the vertical cylinder. Moving the open-ended tube up or down in its aperture varies the distance that it projects into the cylinder, and this in turn varies the degree of difficulty in raising the ball. Easily visible graduations on the cylinder enable the patient to see how high he is raising the ball and thus give a measurement of his progress.