We describe epidemiological trends in HIV among men who have sex with men (MSM) in the United Kingdom (UK) to inform prevention strategies. National HIV surveillance data were analysed for trends. Multivariable analyses identified predictors of late diagnosis (<350 copies/µL) and mortality. Between 1999 and 2013, 37,560 MSM (≥15 years) were diagnosed with HIV in the UK. New diagnoses rose annually from 1,440 in 1999 to 3,250 in 2013. The majority of MSM were of white ethnicity (85%) and UK-born (68%). Median CD4 count increased steadily from 350 cells/µL to 463 cells/µL. HIV testing in England increased from 10,900 tests in 1999 to 102,600 in 2013. One-year death rates after diagnosis declined among late presenters (4.7% to 1.9%). Despite declining late diagnosis (50% to 31%), the number of men diagnosed late annually has remained high since 2004. Older age (≥50 years), and living outside London were predictors of late presentation; older age and late presentation were predictors of one-year mortality. Increases in new diagnoses reflect increased testing and ongoing transmission. Over 900 men present late each year and mortality in this group remains high and preventable. Appropriate prevention and testing strategies require strengthening to reduce HIV transmission and late diagnosis.