P-selectin is a marker of platelet activation. Previous studies have reported elevated P-selectin in patients with congestive heart failure (CHF) and depression as separate disorders. We examined if comorbid depression had an effect on platelet activation in CHF patients. Soluble (s)P-selectin was measured in 108 CHF patients; 24 with comorbid depression. There were no significant differences in age, cardiac parameters or (s)P-selectin levels between CHF-only patients and patients with comorbid depression. Our data show no group differences in P-selectin values, which suggests that comorbid depression has no additive effect on platelet activation in CHF patient.