The efficacy of catheter ablation of atrial fibrillation (AF) remains limited. Increase of success would require more durable lesions without increased risk of steam pop and cardiac perforation. Recently, novel technologies have been developed to estimate real-time catheter-tissue contact force (CF). This paper reviews three available tools for assessment of CF and data on experimental or clinical experience. Experimental data with open-irrigated catheter showed that lesion size was greater with applications of lower power (like 30 W) and greater CF (e.g. 30 to 40 g) than vice versa. Impedance drop in the first 5 seconds was significantly correlated to catheter CF. Perforation was achieved more rapidly with the ablation catheter in a sheath despite the same CF because the sheath prevents catheter buckling. Clinical experience confirmed poor relationship between CF and either unipolar amplitude, bipolar amplitude, or impedance. Within the left atrium, the most common high CF site was found at the anterior/rightward LA roof, directly beneath the ascending aorta (confirmed by merging the CT image and map). Importantly, several studies showed that the use of CF leads to shorter procedure with less fluoroscopy time and less RF applications. CF assessment was also found to be associated with higher proportion of durable lesions. Finally, pilot studies showed that CF measurement could be associated with better clinical efficacy  AF ablation.