High-performance ion-exchange chromatography of myosin using a DEAE-5PW packing was used to purify myosin from skeletal, cardiac and smooth muscle. This method produces high-speed resolution (30-min analysis) of myosin from contaminating myofibrillar proteins. The column has a high capacity for binding myosin (up to 1 g) and can be used for small-scale preparation of highly purified myosin. Gel analysis in the presence of sodium dodecyl sulfate showed recovery of myosin with very little contamination of other myofibrillar proteins. Myosin was also recovered from small biopsy samples (0.1 g) by a direct extraction technique with recovery of biological ATPase activity.