The prevalence of calcium deposits in coronary arteries grows with age. Risk factors include, e.g., diabetes and chronic kidney disease. There are several underlying pathophysiological mechanisms of calcium deposition. Severe calcification increases the complexity of percutaneous coronary interventions. Invasive techniques to modify the calcified atherosclerotic plaque before stenting have been developed over the last years. They include balloon- and non-balloon-based techniques. Rotational atherectomy has been the most common technique to treat calcified lesions but new techniques are emerging (orbital atherectomy, intravascular lithotripsy, laser atherectomy). The use of intravascular imaging (intravascular ultrasound and optical coherence tomography) is especially important during the procedures in order to choose the optimal strategy and to assess the final effect of the procedure. This review provides an overview of the role of coronary calcification for percutaneous coronary interventions.