© 2019 Uchmanowicz et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Development of simple, valid and reliable instruments to determine nursing care rationing is a subject of ongoing research. One such instrument, which is gaining popularity worldwide and has significant research applicability, is the Basel Extent of Rationing of Nursing Care (BERNCA) and its revised version, the BERNCA-R. The aim of this study was to translate and adapt the BERNCA-R into a Polish-language version and to assess its reliability and validity in evaluating the level of implicit rationing of nursing care in Poland. Standard methodological requirements were followed during translation and cultural adaptation of the English version of the BERNCA-R questionnaire into Polish. The cross-sectional validation study was conducted between May and September 2017, which included 175 nurses undergoing specialisation and qualification courses at the European Postgraduate Education Centre in Wrocław, Poland. Cronbach’s alpha and inter-item correlations were used to ana-lyse the internal consistency of the Polish BERNCA-R questionnaire. The mean total BERNCA-R score was 1.9 points (SD = 0.74) on a scale of 0–4. Cronbach’s alpha for the unidimensional scale was 0.96. The mean inter-item correlation was 0.4 (range 0.1–0.84), which indicates high internal consistency. A single-factor solution demonstrated stable loadings above 0.5 for almost all items of the Polish BERNCA-R questionnaire. The study using the Polish BERNCA-R questionnaire demonstrated that the instrument is valid and reliable for use in investigating care rationing in groups of Polish nurses.