Predicting failure following shunting of pleural effusions. We placed 43 shunts in 34 patients in five years. Twenty-four had malignant effusions and ten had benign effusions. Thirty-one patients had unilateral shunts, three had bilateral shunts and six required revisions for shunt failure. Two patients died after shunt placement from disease progression. Of the nine patients who experienced poor results, one was noncompliant in operating the shunt and eight had occluded shunts. In the 30 patients, who were compliant and had adequate length of follow-up, five had excellent results, 12 had good results, and five had fair results. Two of the patients with occluded shunts had good results after shunt revision; 24 patients had some symptomatic relief with shunting. Evaluation of factors including a history of prior abdominal surgery, performance status, and pleural fluid cell counts, differential, chemistries, and cytology revealed no significant differences between the patients who experienced shunt failure and those who had patent shunts. Shunting of pleural effusions is well tolerated and has good success rates in properly selected patients. 