Although the achievement of deep and long lasting remissions is a realistic goal of therapy in the fit patient with chronic lymphocytic leukemia (CLL), this disease typically affects elderly patients who also show one or more concomitant pathological conditions or functional limitations that have an additive effects on the reduction of patient's life expectancy and represent major limitations in the adoption of standard therapies. In these unfit but typical patients with CLL, the goals of treatment may vary from achieving good remissions without severe toxicity to simple palliation. Differently from the past when the definition of patient medical status was mainly based on age and was left to the subjective assessment of the physician, today there are several tools to define in a standardized, reproducible, and multidimensional way the initial patient assessment and to plan treatment goals in an objective way. In this review, an overview of the current approaches to the definition of the medical fitness of the patient is provided along with some practical suggestions to integrate these tools in the clinical approach to elderly patients with CLL.