OBJECTIVES: Psoriasis can significantly impact the well-being of those afflicted. However, the evidence of the impact of psoriasis severity on one’s ability to work and daily activities is inconsistent and limited, respectively. This study aimed to characterize the impact of disease severity on productivity and activities of daily living among Canadians with plaque psoriasis. METHODS: Cross-sectional productivity data were collected via the Work Productivity and Activity Impairment (WPAI) questionnaire from patients at eight Canadian dermatology clinics, and linked to medical chart data. Adults with psoriasis currently working or not working due to psoriasis were recruited, stratified according to severity (by the Psoriasis Area Severity Index; PASI): PASI≤3 (mild); 3<PASI≤12 (moderate); 12<PASI≤20 (moderate/severe); PASI>20 (severe). WPAI data were summarized to estimate the percent of overall work impairment (absenteeism and presenteeism) and activity impairment (activities missed and personal productivity lost). Beta regression modelling estimated the impact of severity on impairment, accounting for relevant covariates (PASI score, psoriasis control, anxiety, depression, and treatment type). RESULTS: A total of 142 patients were included in the study (mild: n=40; moderate: n=41; moderate/severe: n=40; severe: n=21). Mean participant age was 45.7 years; the majority were male (68.3%) Caucasian (77.5%), and employed (100%). The median (interquartile range [IQR]) overall work impairment (%) due to psoriasis was 10(30), increasing with severity: mild = 0(10); moderate = 10(30); moderate/severe = 20(37.5); severe = 20(42.8). The median (IQR) activity impairment (%) due to psoriasis was 10(37.5), increasing with severity:  mild = 0(10); moderate = 10(20); moderate/severe = 20(42.5); severe = 40(70). PASI score was a significant predictor of both work impairment (p <0.01) and activity impairment (p =0.04).   CONCLUSIONS: The negative impact of psoriasis severity on work or daily activities is demonstrated in this study, supporting the need for effective therapies to reduce symptoms that may in turn improve productivity and potentially reduce indirect costs.