This was a multicenter, prospective, 5-year surveillance study of approximately 5000 Raptiva-treated patients and approximately 500 non-Raptiva treated patients (formerly 2500 comparison patients who were treated with a biologic therapy other than Raptiva) with chronic moderate to severe plaque psoriasis who were candidates for treatment with Raptiva.

Inclusion Criteria:

• Have ever had a physician's diagnosis of chronic moderate to severe plaque psoriasis and be a candidate for treatment with Raptiva
• Are being treated with or initiating Raptiva therapy at the time of enrollment
• Be able to provide written informed consent
• Be willing and able to fully to participate for the duration of patient follow-up (5 years)

Exclusion Criterion:

• Have previously received at least one dose of Raptiva and are not currently using or restarting treatment with Raptiva at the time of enrollment

managed care organizations, community or physician practices, and academic centers in the United States