The peripheral blood absolute lymphocyte count (ALC) recovery after autologous stem cell transplantation has been shown to be an independent prognostic factor for survival for different haematologic malignancies. The role of ALC at diagnosis for follicular (grades 1 and 2) lymphomas (FL) on survival is not well described. The primary objective of this study was to assess the role of ALC on overall survival (OS) in FL patients. Of 1104 FL patients, 228 patients were originally diagnosed, followed, and had all treatment at the Mayo Clinic from 1984 and 1999, were evaluated. The median follow-up was 89 months (range: 8.35-248). ALC as a continuous variable was identified as a predictor for OS [Hazard ratio (HR) = 0.74, P < 0.04]. ALC >/= 1.0 x 10(9)/l (n = 164) predicted a longer OS versus ALC < 1.0 x 10(9)/l (n = 64; 175 vs. 73 months respectively, P < 0.0001). When compared with the Follicular Lymphoma International Prognostic Index (FLIPI), ALC was an independent prognostic factor for OS by multivariate analysis (HR = 0.677, P < 0.0001). These data suggest a critical role of FL patients' immune status at diagnosis on survival.