OBJECTIVES: To refine and evaluate the validity and reliability of the Hyperpigmentation Treatment Satisfaction Questionnaire (HPTSQ). The HPTSQ was designed to measure medication treatment satisfaction for subjects with hyperpigmentation, either melasma (pregnancy mask) or solar lentigines (age spots). METHODS: All analyses were conducted on data from a cross-sectional sample of subjects who reported having hyperpigmentation and completed the HPTSQ online. RESULTS: A total of 635 respondents (573 with solar lentigines and 62 with melasma) completed the HPTSQ. Factor analysis, Item Response Theory (IRT) and traditional psychometric analyses were used to select the 26 items in five factors/ domains from an initial pool of 38 items. These five domains had the following properties: 1) Efficacy - 7 items, á coefficient 0.96; 2) Side Effects - 5 items, á coefficient 0.95; 3) Physical Properties - 5 items, á coefficient 0.88; 4) Convenience - 5 items, á coefficient 0.87; and 5) Overall Satisfaction – 4 items, á coefficient 0.93. Domains 1, 3, 4, and 5 showed strong test-retest reliability (intra-class correlations 0.77-0.87), while Domain 2 had an ICC of 0.44 (0.52 for subjects reporting side effects at both baseline and follow-up). All domains of the HPTSQ showed strong construct validity when correlated with related domains on three comparable patient-reported instruments. Based on level of treatment satisfaction, all domains of the HPTSQ showed strong known-groups validity (p<0.01), except Domain 2 (Side Effects). CONCLUSIONS: The 26-item HPTSQ is a psychometrically sound and valid measure of solar lentigines and melasma subjects' treatment satisfaction with medication. Responsiveness testing of the HPTSQ should be conducted in a prospective clinical trial.