Haemophagocytic syndrome is often associated with malignant lymphoma; however, few studies have examined lymphoma-associated haemophagocytic syndrome (LAHS). A total of 1239 patients with non-Hodgkin lymphoma were analysed at 12 institutions in Hokkaido prefecture between January 2007 and December 2011 to assess the incidence, prognosis and risk factors of LAHS. The cumulative incidence rate of LAHS was 2·8% (35/1239). Overall survival (OS) in patients with LAHS was significantly inferior to those without LAHS (3-year OS: 35·6 vs. 59·0% respectively, P < 0·0001). The cumulative incidence of LAHS was higher in patients with T/Natural Killer (NK)-cell lymphoma than in those with B-cell lymphoma (8·2 vs. 1·8% respectively, P < 0·0001). The characteristics of patients with and without early death (within the first 120 d after developing LAHS) were subsequently compared to evaluate the prognostic factor of LAHS. The results obtained showed that the rate of early death after developing LAHS was higher in patients with T/NK-cell lymphoma than in those with B-cell lymphoma (62·5 vs. 10·5%, P = 0·0033). In conclusion, the complication and mortality rates of LAHS were higher in patients with T/NK-cell lymphoma after they developed LAHS than in those with B-cell lymphoma.