INTRODUCTORY SOCIOLOGY STUDENTS AT A CANADIAN UNIVERSITY WERE ASKED IN A CHECKLIST QUESTIONNAIRE ABOUT THEIR PERCEPTIONS OF THE CERTAINTY AND SEVERITY OF PUNISHMENT FOR MARIJUANA USE AND SHOPLIFTING AND FOR THEIR PERSONAL HISTORIES OF THESE ACTS. THE HYPOTHESES FOR THE STUDY WERE: 1) THOSE RESPONDENTS WHO PERCEIVE HIGHER CERTAINTY AND SEVERITY OF PUNISHMENT WOULD ENGAGE IN LESS MARIJUANA USE AND SHOPLIFTING THAN THOSE WHO PERCEIVE LOWER CERTAILTY AND SEVERITY; 2) THE DETERRENT EFFECTS OF PUNISHMENT SHOULD BE GREATER FOR MARIJUANA USE THAN FOR SHOPLIFTING; 3) HIGH PERCEIVED SEVERITY SHOULD BE MOST SALIENT UNDER CONDITIONS OF HIGH CERTAINTY: AND 4) THAT HAVING A FRIEND ARRESTED SHOULD BE POSITIVELY ASSOCIATED WITH MARIJUANA USE AND SHOPLIFTING. THE RESULTS OF THE SURVEY SUPPORTED THE FIRST HYPOTHESIS, BUT FOR MARIJUANA USE ONLY. HYPOTHESES THREE AND FOUR RECEIVED SOME SUPPORT, WHILE HYPOTHESIS TWO WAS ONLY PARTIALLY SUPPORTED.