OBJECTIVES: COLLECT scale was developed to assess the level of comorbidity with an impact on treatment decision for patients with Chronic Lymphocytic Leukaemia (CLL) in 5 steps: 1.-Literature review, 2.-Focus Group, 3.-Pilot study to evaluate scale feasibility, 4.-Scale design, 5.-Scale validation in an observational, prospective phase IV study (evaluating safety profile of Rituximab in CLL). This communication presents the preliminary validation of the COLLECT scale. METHODS: A total of 219 patients were included. The scale is to be fulfilled before initiating CLL treatment and it collates and rates the presence of 11 relevant comorbidities. The range of the score goes from 0 to 57 points.  Four scoring clusters were predefined: 0-3 points (low comorbidity), 4-6 (mild comorbidity), 7-10 (moderate comorbidity) and >10 (high comorbidity). RESULTS: Data from 218 patients of 47 hospitals were analyzed. Most frequent therapeutic scheme was Rituximab-Fludarabine-Cyclophosphamide (R-FC) (41.3%), followed by Rituximab-Bendamustine (R-B) (29.6%) and Rituximab-Chlorambucil (R-Cl) or schemes including alkylating agents (21.1%). COLLECT median score (SD) was 4 (0-21) with a mean of 4.8 (3.1) points. 39.2% of patients scored between 4-6 and 33% between 0-3. Statistically significant differences were observed in COLLECT score according to age (p<0.01) and EGOG (p<0.01): the greater the age and ECOG, the greater the score. The election of inmunochemotherapy treatment differed depending on the score cluster (p=0.002): 50.6% and 32,9% of patients treated with R-FC had low and mild comorbidity level respectively. 40,0% of patients receiving R-B had medium and 26.5% high comorbidity level. 50% of patients treated with R-Cl scored between 4-6 and the 23.5% between 7-10. CONCLUSIONS: COLLECT scale allows defining 4 levels of comorbidities, with a very good correlation to age and ECOG status. Although the aim of the scale is not to drive treatment decision, the study shows a trend to associate comorbidity score with intensity of treatment.