Abstract: A magnetic stirring device which also provides for simultaneous heating/cooling of samples. The magnetic stirring apparatus comprises a plurality of wells into which respective vessels can be placed and continuously stirred by motivating a magnetic stirring bar therein with a three phase frequency controller. Simultaneously, the temperature of the vessels can be maintained at a predetermined temperature either above or below room temperature by means of thermoelectric elements in contact with a heat conducting block within which the wells are located.