Fifty-two consecutive patients ranging in age from 22 to 90 years underwent percutaneous transthoracic fine needle aspiration biopsy under fluoroscopic guidance. A quick staining and rapid interpretation technique was used on samples from the 37 most recent cases. Rapid staining was accomplished within five minutes, and interpretation was available less than 15 minutes after obtaining the specimen. Successful diagnosis was obtained in 36 of 37 patients (97%). Standard methods utilizing a single aspiration sample yielded a successful diagnosis in 13 of 15 patients (86%). The improved rate of successful diagnosis following the rapid stain technique reflects the advantage of being able to determine the adequacy of specimens before releasing patients from the procedure room.