Aim: The aim of this study was to determine the number, indications and results of diagnostic NGS tests performed at the Faculty of medicine in Rijeka, Croatia since its implementation. Materials and Methods: A retrospective study was performed from 2017 to 2021 and included the analysis of referral diagnoses and NGS test reports of patients who were referred to the Faculty of Medicine in Rijeka for diagnostic NGS testing from Clinical Hospital Center Rijeka. NGS was performed in collaboration with the Clinical Institute of Genomic Medicine in Ljubljana (Slovenia), using Illumina NovaSeq 6000 (Illumina Inc). Results: During 2017 was worked on the establishment of the system, and for this purpose, numerous educations and interviews with clinicians were organized. From April 2018 to December 2021, a total od 118 diagnostic NGS were performed, including 8 in 2018 (7 %), 29 in 2019 (25 %), 42 in 2020 (35 %) and 39 in 2021 (33 %). From 2018, the number of NGS testing increase by 425% in 2019, from 2019 to 2020 by 141%, from 2020 to 2021 it decrease by 8%. The most common indications for testing were neuromuscular diseases (41 %), cardiomyopathies (19 %) and multiple congenital anomalies (15 %). Positive test results were obtained in 53/118 (45 %) cases in whom likely pathogenic (26 %) or pathogenic sequence variants (49 %) were determined. Class 3 sequence variants were identified in 13 (11 %) cases. In 65/118 (55 %) cases no genetic aberration could be found. Out of the total number of positive findings, 75 % of referral diagnoses were confirmed and only 34% of the total number of findings. Conclusion: Our results show an increase in the number of diagnostic NGS tests from 2017 to 2021, which reflects the increased awarness of clinicians for the need of genomic testing in clinical practise. Unfortunately, the large number of incorrect indications for genetic testing, indicates that genetic education of clinicians is needed for an improved diagnostic yield.