Follicular lymphoma (FL) is a heterogeneous disease. For many it is experienced as a chronic, relapsing, indolent condition with long overall survival (OS). Most people affected have advanced disease at presentation; symptoms may include B symptoms (i.e. fever, night sweats and weight loss), fatigue and the local mass effect of lymph node enlargement. However, many people are asymptomatic at presentation. Some people are observed without treatment according to a ‘watch and wait’ policy (see section Management of patients with newly diagnosed FL). In contrast to this, over a period of many years, 20–30% of patients will die from refractory FL or following transformation of their disease to high‐grade lymphoma.1 Prognostic indices may help discriminate between risk groups (see section Prognostic factors in FL).