Background Autosomal dominant polycystic kidney disease (ADPKD) is the most common renal monogenic disease and characterized by bilateral accumulation of renal fluid-filled cysts leading to progressive renal volume enlargement and gradual impairment of kidney function which often resulting in ESRD. Kuwait could provide valuable genetic insight about ADPKD including intrafamilial phenotypic variation, given its large household size. This study aims to provide a comprehensive description of the pathogenic variants linked to ADPKD in the Kuwaiti population using multiple genetic analysis modalities and to describe and analyze the ADPKD phenotypic spectrum in term of kidney function, kidney volume and renal survival. Methods 126 ADPKD patients from 11 multiplex families and 25 singletons were recruited in the study. A combination of targeted next generation sequencing (tNGS), long range (LR) -PCR, Sanger sequencing and multiplex-ligation dependent probe amplification (MLPA) were utilized for genetic diagnosis. Clinical evaluation was conducted through Renal Function Test (RFT) and ultrasonographic kidney volume analysis. Results We identified 29 ADPKD pathogenic mutations from 36 families achieving an overall molecular genetic diagnostic rate of 112/126 (88.9%) including 29/36 (80.6%) in families. 28/36 (77.8%) of families had pathogenic mutations in PKD1, of which 17/28 (60.7%) were truncating, and 1/36 (2.8%) had a pathogenic variant in IFT140 gene. 20/29 (69%) of the identified ADPKD mutations were novel and described for the first time including a TSC2-PKD1 contiguous syndrome. Clinical analysis indicated that genetically unresolved ADPKD cases had no apparent association between kidney volume and age. Conclusion We describe for the first time the genetic landscape of ADPKD in Kuwait. The observed genetic heterogeneity underlining ADPKD along with the wide phenotypic spectrum reveals the level of complexity in disease pathophysiology. ADPKD genetic testing could improve care of patients through improving disease prognostication, guided treatment, as well as genetic counseling. However, to fulfill the potential of genetic testing, it is important to overcome the hurdle of genetically unresolved ADPKD cases.