Our aim was to prospectively assess the prognostic value of beta2-microglobulin (b2-M) in patients with acute pulmonary embolism (PE). We conducted a prospective study of 109 patients admitted in a pulmonary clinic due to acute PE. A panel of inflammatory markers including b2-M white blood cell (WBC) count and C-reactive protein (CRP) was determined for each patient. In this preliminary study, baseline b2-M levels significantly correlated with the impairment of oxygenation and with all the parameters that are used for the early risk stratification of patients. In multivariate analysis, patients' age and baseline b2-M levels were significantly associated with an increased risk of death. These findings require further prospective validation.