A total of 1,253 students (805 females and 448 males) from two colleges in upstate New York participated in this study. Of this sample, 16 percent were 18 years old or younger, 52 percent were 19 to 20 years old, and 32 percent were 21 or older. A questionnaire entitled "Halloween Activities" was administered each year between 1978 and 1982 to students in social science classes. Students were asked whether or not they wore a costume, whether they celebrated by drinking, whether they celebrated by smoking marijuana, and whether they celebrated by using any other drugs. A chi- square statistical procedure was used to test whether or not a relationship existed between the wearing of costumes and the use of alcohol and other drugs. Findings indicate that, for college students, dressing in costume on Halloween is associated with the use of alcohol. No significant associations were found between wearing a costume and smoking marijuana or using other drugs. The association between dressing in costume and the use of alcohol does not imply a cause-effect relationship. Halloween is often considered a time for parties and celebration among college students, and dressing in masquerade costume is a core activity of the Halloween celebration. Alcohol consumption among college students is also associated with parties and celebration. 3 tables and 23 references