Caring for residents in long-term care who suffer from dementia is a special challenge. In the context of a research project a questionnaire for a mail survey in nursing homes was developed in order to describe specific nursing interventions for dementia in daily practice. The Questionnaire development was done according to acknowledged standards for questionnaire development, using means of operationalisation and external expert rating. Then the questionnaire was tested in a two-phase-pretest. Seven nursing homes were involved in a cognitive pretest. The standard-pretest was sent to 200 nursing homes (response rate 17.5 percent). Evaluation of the questionnaire drafts by means of two-phase-pretesting proved to be an effective measure for continuous improvement. The resulting questionnaire should be used to collect data about specific interventions for people suffering from dementia in residential long-term care.