Medication nonadherence is a significant problem in psoriasis. Although previous research has aimed to quantify the prevalence of nonadherence in topical medication users, patient motivations for intentional nonadherence are not fully understood. Our purpose was to determine the relative importance of factors contributing to nonadherence in topical corticosteroid users with psoriasis. A survey was distributed to psoriasis patients visiting an outpatient clinic. Among the 53 persons surveyed, medication nonadherence was 40%. Frustration with medication efficacy, inconvenience, and fear of side effects were the most important reasons patients deviated from usage instructions. Subjects who did not receive instructions on topical treatment duration used corticosteroids longer (>8 weeks) than subjects who were instructed (P < .05). A relatively small sample size prevented trends in demographic predictors of adherence from reaching statistical significance. The patient self-report format has the potential to introduce recall bias. Factors contributing to intentional nonadherence, including dissatisfaction with efficacy, inconvenience, and fear of side effects, are the most important patient-identified barriers to appropriate use of topical steroids in psoriasis. Clear patient instructions on the intended steroid treatment duration may reduce adverse effects from overuse.