The authors examined cognition and functional health of 57 patients with sinus thrombosis 1 year or more after enrollment in a randomized trial of anticoagulant treatment or placebo. Eight patients died and two declined participation. Of the remaining 47 patients, 16 (35%) had cognitive impairments, 3 (6%) were dependent, 19 (40%) had symptoms that led to restrictions in lifestyle, and 19 (40%) could not resume their previous level of economic activity. Outcome after sinus thrombosis may be less favorable than reported previously, and was not significantly influenced by treatment.