Three types of experiments were conducted in a study of flow-induced vibration of cylinders: 1) experiments with a single cylinder in the test section, in which the length, mass, flexural rigidity, and diameter of the cylinder, and the flow velocity were varied systematically, in order to obtain a measure of the dependence of vibration amplitude on these parameters; 2) ad hoc experiments with single cylinders on the effect of large-scale flow disturbances upstream of the cylinder; 3) experiments with a bundle of cylinders. Based on the work of 1), a previously derived empirical expression for predicting vibration amplitude was revised, and agreement with the experimental data from various sources was improved; however, agreement with the experiments of 3) remains poor.