Among an inner London UK cohort of 147 adolescents transitioning from paediatric into adult care between 2007 and 2015, a new diagnosis of lymphoma was made in five patients; incidence rate = 0.425/100 person-years (95% confidence interval = 0.424-0.426). Previously described risk factors, including low nadir CD4 cell count and ongoing HIV-1 viraemia, appeared to be important. These data suggest that careful surveillance and a low threshold for investigating relevant symptoms continue to be essential for such patients.