Introduction:HIV cohort data from high-income European countries were compared with the UNAIDS Spectrum modelling parameters for these same countries to validate mortality rates and excess mortality estimates for people living with HIV (PLHIV) on antiretroviral therapy (ART).Methods:Data from 2000 to 2015 were analysed from the Antiretroviral Therapy Cohort Collaboration (ART-CC) for Austria, Denmark, France, Italy, the Netherlands, Spain, and Switzerland. Flexible parametric models were used to compare all-cause mortality rates in the ART-CC and Spectrum. The percentage of AIDS-related deaths and excess mortality (both are the same within Spectrum) were compared, with excess mortality defined as that in excess of the general population mortality.Results:Analyses included 94026 PLHIV with 585784 person-years of follow-up, from which there were 5515 deaths. All-cause annual mortality rates in Spectrum for 2000-2003 were 0.0121, reducing to 0.0078 in 2012-2015, whilst the ART-CC's corresponding annual mortality rates were 0.0151 [95% confidence interval (95% CI): 0.0130-0.0171] reducing to 0.0049 (95% CI: 0.0039-0.0060). The percentage of AIDS-related deaths in Spectrum was 74.7% in 2000-2003, dropping to 43.6% in 2012-2015. In the ART-CC, AIDS-related mortality constitutes 45.3% (95% CI: 38.4-52.9%) of mortality in 2000-2003 and 26.7% (95% CI: 19-46%) between 2012 and 2015. Excess mortality in the ART-CC was broadly similar to the Spectrum estimates, dropping from 75.3% (95% CI: 60.3-95.2%) in 2000-2003 to 30.7% (95% CI: 25.5-63.7%) in 2012-2015.Conclusion:All-cause mortality assumptions for PLHIV on ART in high-income European settings should be adjusted in Spectrum to be higher in 2000-2003 and decline more quickly to levels currently captured for recent years.