von Willebrand disease (VWD) is the most frequent inherited bleeding disorder with an estimated symptomatic prevalence of 1 per 1,000 in the general population. VWD is characterized by defects in the quantity, quality, or multimeric structure of von Willebrand factor (VWF), a glycoprotein being hemostatically essential in circulation. It is classified into three principal types; Low VWF/type 1 with partial quantitative deficiency of VWF, type 3 with virtual absence of VWF, and type 2 with functional abnormalities of VWF, being classified as 2A, 2B, 2M and 2N. A new VWD type has been recently discussed by the joint ASH/ISTH/NHF/WFH 2021 guidelines (i.e., type 1C) indicating patients with quantitative deficiency due to an enhanced VWF clearance. With the advent of next-generation sequencing technologies, the process of genetic diagnosis has substantially changed and improved accuracy. Therefore, nowadays patients with type 3 and severe type 1 VWD can benefit from genetic testing as much as type 2. Specifically, genetic testing can be used to confirm or differentiate a VWD diagnosis, as well as to provide genetic counseling. The focus of this manuscript is to discuss the current knowledge on VWD molecular pathophysiology and the application of genetic testing for VWD diagnosis.