The effect of humor on retention of information was examined. The planetarium at COSI, Ohio’s Center of Science & Industry in Columbus, was the source of the study. General public museum visitors were the subjects. A total of 495 adult subjects, ages 18 and older, were involved. Subjects were presented with one of two versions of a 15-minute taped general astronomy show. The two versions were identical except that one had humorous inserts. The humor in the humorous version was related to and integrated with the educational material and was presented at a fast pace. Humor was placed every 90 seconds in the middle of the concept being explained. A total of 20 concepts were described in the show, 10 of which had humorous inserts and which alternated with the 10 nonhumorous concepts. After the show visitors received a 20-question test to determine their short-term retention of the information. The questions were taken directly from the show’s script. The test was of a fill-in-the-blank format. Results indicated that the visitors who saw a humorous show had less retention of the instructional material and scored lower on the test than visitors who saw a nonhumorous show.