The Young Schema Questionnaire (YSQ) measures the intensity of early maladaptive schemas connected with symptoms of mental disorders, particularly personality disorders. We conducted a procedure of shortening the Polish version of the YSQ, analogous to the original one, and determined the psychometric properties of the instrument thus developed by performing a reliability and validity analysis (n = 1.073). In the second part of the study we tested the factor structure of the YSQ using confirmatory factor analysis in the sample from Study 1 and an independent group (n = 898). We reduced the number of items in the questionnaire from 232 to 90 – leaving five items in each of the 18 scales corresponding to specific schemas. We obtained adequate and high internal consistency coefficients for each subscale and for the whole instrument. The overall measure of schemas was positively associated with beliefs characteristic for all personality disorders measured by the Personality Beliefs Questionnaire (PBQ). The intensity of the schemas (except the Self-Sacrifice scale) significantly differentiated participants from the clinical (n = 31) and nonclinical groups (n = 1,042). We also confirmed the theoretical factor structure of the instrument, although the weakness of some measures of fit suggests the need for further research. The obtained results support the use of the experimental short Polish version of the Young Schema Questionnaire as a measure of early maladaptive schemas.