We report a solitary fibrous tumor in the nasal cavity of a 48-year-old woman who presented with a history of bilateral nasal obstruction and long-standing cocaine inhalation. Physical examination revealed a large mass involving the right nasal cavity and extending into the posterior aspect of the left nasal cavity. The computed tomography scan showed opacification of airways. During surgery, the mass was found to involve the entire nasal cavity, with extension to the right maxillary sinus, posterior nasal airways, and left nasal cavity. The mass was completely excised. Pathologic examination revealed a polypoid mass 3.7 x 3.0 x 1.2 cm. This tumor was composed of spindle cells that were cytologically bland in a background of ropey and nodular collagen, giving a "patternless" pattern. Immunohistochemically, the neoplastic cells stained for CD34 and vimentin but not for S100 protein, keratin, desmin, HMB-45, and c-Kit. This immunohistochemical pattern confirmed the diagnosis of solitary fibrous tumor. Although solitary fibrous tumors are usually found in the pleura, they can occur in various other locations, such as the orbit, nasal cavity, paranasal sinuses, mediastinum, breast, vagina, meninges, and soft tissues. This case is of interest because the tumor occurred in a patient with prolonged cocaine inhalation. Such an association has not been previously described. The exact causal relationship between cocaine inhalation and the tumor is not known.