There is evidence that immunological factors may be involved in pathogenic mechanisms of amyotrophic lateral sclerosis (ALS). Interleukin (IL)-15 and IL-12 are proinflammatory cytokines produced by activated blood and glial cells. They promote T cell differentiation and proliferation. We measured by ELISA serum and cerebrospinal fluid (CSF) levels of IL-15 and IL-12 in 21 patients with ALS and 19 patients with other noninflammatory neurological disorders (NIND) studied as a control group. IL-15 and IL-12 serum and CSF levels were also correlated with duration of the disease, the disability level determined using the revised ALS Functional Rating Scale and the clinical subtype of the disease onset in patients with ALS. IL-15 and IL-12 serum levels were higher in patients with ALS as compared with patients with NIND (p= 0.014 and p= 0.011, respectively). IL-15 and IL-12 CSF levels were also increased in patients with ALS (p= 0.011 and p= 0.005, respectively). IL-15 and IL-12 levels were not correlated with disease duration, disability scale or clinical subtype of the disease onset in ALS patients. Our findings suggest that these molecules may be involved in the pathogenic mechanisms acting as potential markers of immune activation in ALS.