OBJECTIVES: To evaluate the equivalence of electronic and paper versions of the Psoriasis Symptom Inventory (PSI) and examine measurement properties of the electronic version. METHODS:  In a prospective, randomized, cross-over, non-interventional study in adult subjects (age ≥ 18 years) with plaque psoriasis conducted over a 15-day period , subjects were randomized to two groups, each completing either the paper or electronic PSI daily for 7 consecutive days followed by the alternate version. The disease specific Dermatology Life Quality Index [DLQI]) and the generic SF36v2 were also administered for evaluation of construct validity. Equivalence was assessed by the intraclass correlation coefficient (ICC) between both modes. Differences in scores between the administration modes were also tested using paired Student’s t-test. Measurement properties included internal consistency reliability, test-retest reliability, and construct validity. Convergent and discriminant validity were evaluated using pre-identified logical relationships between similar or distally related concepts. RESULTS: Eighty subjects (74 % [59/80] moderate-to-severe psoriasis; 26% [21/80] mild psoriasis receiving systemic treatment) were enrolled from 8 sites in the United States. Seventeen (21%) subjects experienced a change in sPGA and were excluded from analyses. The paper and electronic modes of the PSI were highly concordant for both total scores (ICC = 0.969) and individual item scores (ICC range 0.934 to 0.965). Findings remained consistent (ICC values were all >0.91) irrespective of order of completion for the paper and electronic versions. All mean score differences were non-significant (p > 0.05) except for “flaking”; however, based on its reliability, validity, and clinical relevance, the item was retained . Minimum values for reliability (> 0.70) and validity (convergent, r ≥ 0.30) were exceeded for the electronic PSI. CONCLUSIONS: Equivalence between paper and electronic versions of the PSI and the two modes’ comparable measurement properties indicated successful migration from paper to electronic format of the PSI.