A study has been carried out on the basis of a field experiment set up on soil of very good rye complex. The experiment was designed as randomized sub-blocks with three replications. Experimental factors included three cultivars of edible potato – Wiking, Mors, and Żagiel, and six Colorado potato beetle control methods using the following insecticides: Actara 25 WG at the rate of 80 g ha-1, Regent 200 SC at the rate of 0.1 dm3 ha-1, Calypso 480 SC at three rates: 0.05; 0.075 and 0.1 dm3 ha-1, and a control treatment without chemical protection. Magnesium and calcium contents in potato tubers were determined by the ASA method. The content of the elements depended on the cultivars, Colorado potato beetle control methods and weather conditions throughout the growing season. The insecticides applied significantly increased magnesium and calcium contents compared with the tubers harvested from the control treatment where no chemical protection was applied. Tubers of Żagiel and Wiking cultivars had the highest magnesium content and calcium content, respectively.