Purpose This study aimed to examine treatment of T1b-T4 melanoma at MIA, especially the rates of sentinel node biopsy (SNB). The impact of primary tumour features and patient factors were examined to see if these play a role on survival and patient outcomes. Methodology From the prospectively maintained MIA database, 14,234 patients were identified with primary cutaneous melanomas staged as T1b-T4 and treated at the MIA between 1 January 2000 – 31 December 2019. The data was analysed examining differences in demographic data, residence + SES score, melanoma characteristics and survival vs recurrence rates. Multivariate analysis and cox regression were performed. Results •Overall SNB rate was 56% with a positive rate of 19%. The group most likely to undergo SNB was T3a (67.3%) and least likely T1b (29.2%) •Head and neck primaries (21%) were less likely to have SNB compared to truncal primaries (31%) •The highest proportion of T4b were from the most disadvantaged population (29.4%) compared to any other stage indicating possibly a delay in presentation. •Patients who were clinically staged as T4a or T4b were less likely to get a SNB than tumours staged T2-T3 •There was no significant survival benefit to SNB vs wide excision only on multivariate analysis. However, patients who had SNB had a greater period of recurrence free survival Conclusion This study describes the treatment of T1b-T4 melanomas in the largest melanoma unit in Australia. The rates of SNB appear to be higher compared to other Australian data.