OBJECTIVES: Current questionnaires assessing the impact of nocturia (waking up at night one or more times to void), e.g. N-QoL, ICIQ-N or IPSS, do not fulfill the new FDA PRO guidelines. We report on the development of a new nocturia impact measure. METHODS: The following recommended steps were undertaken: 1) Literature review identifying an exhaustive pool of concepts, hereafter development of draft diary; 2) Cognitive debriefing test (n=23) confirming relevance and importance of items and understandability of phrasing. Preliminary Rasch analysis. Modified diary developed and 3) Reliability, validity, sensitivity and dimensionality tested in randomized, placebo-controlled trial (n=56). RESULTS: Step 1 generated 4 domains including 14 items with 5 response options (‘a great deal’ to ‘not at all’). Step 2: Content validity supported 11 items and suggested 1 new. Revision into a 12-item diary with 2 domain scores. Step 3: Dimensionality:  Factor and Rasch analyses clearly indicated uni-dimensionality.  Construct Validity: Known group validity (<3/≥3 voids): Total score D-13.6 points at baseline, p=0.03. Fit to Rasch model at baseline 2 of 3 p= >0.05. Reliability: Stability over time=0.91. Internal consistency:  Cronbachs alpha=0.9. Sensitivity: Cohen’s D=0.73. High variance in response options, slight floor effect.  Person correlation with number of voids=0.31, p=0.02. Final NI diary: Nocturia Impact total score calculated from 11 core items. Global impact question (Q12) analyzed separately. CONCLUSIONS: All validity and reliability tests of the Nocturia Impact Diary® were highly supportive. The sensitivity was acceptable, especially the calculation of Cohen’s D based on pooled analysis. The Nocturia Impact Diary® is the first nocturia impact assessment tool developed in close dialog with FDA and in accordance with the new PRO guidelines.  Consequently, it represents a valid new tool within nocturia and should be used in conjunction with voiding diaries in cross sectional assessments of patient burden or in assessments of changes due to treatment of nocturia.