Patient classification in anaesthetic care is an undeveloped field and it is therefore urgent to construct an instrument for this purpose. The aim of the study was to develop an instrument to measure anaesthetic nursing care with focus on the unique care needed by every single patient. The Delphi technique was used. The method involved five series of inquiries to a panel of experts, consisting of ten nurses. The instrument developed, included 13 nursing care areas, with predefined alternatives graded from1 to 4, where 4 indicated high workload, and 1 indicated low workload. The instrument was tested in a pilot study and showed agreement with the clinical picture of the patients needs. An initial inter-rater reliability test showed very good agreement for all the nursing care areas. The instrument, however, needs to be tested for validity and reliability in a larger sample.