The effects of almond consumption on DNA damage and oxidative stress among cigarette smokers were studied. Thirty healthy adult male regular smokers were randomly divided into three groups, 10 subjects per group. Group A (control group) did not receive any almonds. Subjects in Groups B and C received 3 oz and 6 oz (84 g and 168 g) of almonds each day respectively for 4 wk. Two known biomarkers for DNA damage, urinary 8-hydroxy-2'-deoxyguanosine (8-OH-dG) and single strand DNA breaks of peripheral blood lymphocytes, were measured by enzyme-linked immunosorbent assay and comet assay, respectively. In addition, plasma malondialdehyde (MDA) level, superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activities were measured as biomarkers for oxidative stress. The results showed lower levels of urinary 8-OH-dG and single strand DNA breaks in the two almond-treated groups as compared with the control group. Furthermore, MDA levels in the almond-treated groups were lower than the controls. However, no significant effects of almonds on SOD and GSH-Px activities were found. In conclusion, results from this pilot study indicate that almond consumption has preventive effects on oxidative stress and DNA damage caused by smoking. A larger, randomized, placebo-controlled clinical trial on almonds will be initiated in the near future.