BACKGROUND: Initiating therapy with a low CD4 cell count is associated with a substantially greater risk of disease progression and death than earlier initiation. We examined factors associated with late presentation of HIV using the new European consensus definition (CD4 cell count <350 cells/mm3) and mortality. METHODS: Patients newly diagnosed with HIV infection at a UK clinic were recruited from January 1996 to May 2010. Factors associated with late presentation were assessed using logistic regression. Factors associated with mortality rates were analysed using Poisson regression. RESULTS: Of the 1536 included in the analysis, 86% were male and 10% were aged 50 years and older. Half the cohort (49%) had a CD4 cell count below 350 cells/mm3 at presentation ("late presentation"). The frequency of late presentation was highest in those aged 50 years or older and remained unchanged over time (64.3% in 1996-1998 and 65.4% in 2008-2010). In contrast, among those aged less than 50 years, the proportion with late presentation decreased over time (57.1% in 1996-1998 and 38.5% in 2008-2010). Other factors associated with late presentation were African ethnicity and being a male heterosexual.The mortality rate was 15.47/1000 person-years (pyrs) (95%-CI: 13.00-18.41). When compared with younger adults, older individuals had a higher mortality, after adjusting for confounders (rate ratio (RR) = 2.87; 95%-CI: 1.88-4.40). CONCLUSIONS: Older adults were more likely to present late and had a higher mortality. Initiatives to expand HIV testing in clinical and community setting should not neglect individuals aged over 50.