Background: Muscle biopsy (MBx) is one of the key investigations in children with suspected neuromuscular disorders (NMD). In cases with a wide differential diagnosis, a MBx helps with the early diagnosis and therefore prevents any delay in treatment. In children a MBx often needs to be performed under general anaesthesia. Objective: To evaluate the effect of the Covid-19 pandemic and the advances in genetic testing have had on the total number of MBx performed at a tertiary centre between April 2014 and April 2022. Methods: Retrospective case records of patients who underwent MBx between April 2014 and April 2022 were reviewed. Investigations including genomic testing, number of biopsies and referrals, waiting time and the final diagnosis were collected and analysed. Results: We reviewed a total of 102 children (101 children underwent a MBx, 70 skin biopsy and 4 nerve biopsies). The average number of biopsies per year was 14.2 biopsies during the pre-pandemic period & 8.5 biopsies during the post pandemic period. This represents a 40% reduction within the last 3 years. The median waiting time from referral till the date of biopsy was 96.5 days during the pre-pandemic period (p value: 0.013, CI: 36.1-266.4) and 143 days during the post pandemic period (p value: 0.0, CI: 71.8-230.6). During the last 3 years, in 100% of the patients who underwent a MBx, a genetic test was also done at some point during evaluation. In 28.4% (29 out of 102) of the biopsies’ results were specific for the diagnosis. MBx and genetic testing did not identify a diagnosis in 38% of the patients. In 11.7% of the cases (6 myositis, 6 mitochondrial, 2 Neuropathy) muscle biopsy picked up the non-genetic diagnosis or directed us to further testing. Conclusion: The number of biopsies and referrals has significantly decreased in the last 3 years, which could be related to the pandemic and/or advances in genetic testing. The diagnostic strategy of some NMDs has been modified and the utility of MBx in this process has been questioned. The role of the MBX is never likely to disappear completely as many non-genetic NMD remain challenging and will be easily missed even with the most sophisticated genetic tests. (Word count 358).