Although serum beta2 microglobulin (beta2 M) is an easy parameter to measure, and over-expressed in a large number of lymphoproliferative diseases, its prognostic value has been largely underestimated. The present study examined the influence of beta2M levels on overall survival (OS) of patients with follicular lymphoma (FL).The prognostic role of beta2M was evaluated in 236 patients with FL identified from the databases of the Gruppo Italiano per lo Studio dei Linfomi (GISL) and treated with anthracycline-based regimens from 1993 to 2003.Elevated serum beta2M levels were found in 82 patients (35%). According to multivariate logistic regression analysis, elevated beta2M levels were associated with elevated lactate dehydrogenase (LDH) (p=0.021), age (p=0.029), and number of involved nodal areas (p<0.001). The percentage of elevated beta2M levels increased progressively with increasing FLIPI scores (17%, 38%, and 63% in the low-, intermediate-, and high-risk groups, respectively). Five-year OS was 61% (95% CI, 47-73%) and 89% (95% CI, 82-93%) for patients with elevated vs normal beta2M levels respectively (p<0.001). Cox regression analysis showed that beta2M level had an independent and stable prognostic value (HR=3.0; 95%CI, 1.6-5.7). In a multivariate analysis the impact of beta2M level on survival was independent of FLIPI score, with a HR of 2.94 (95% CI, 1.54-5.62).Our results demonstrate that in patients treated in the pre-rituximabera, beta2M level was an independent prognostic marker in addition to FLIPI score. We thus suggest that beta2M be routinely assessed and tested in future prognostic studies of FL patients treated with combination chemotherapy and anti-CD20 agents.