Guided by the i-PARIHS framework, this study investigates perceived facilitators in the process of adopting a new regulation launched in 2015 which aims to prevent and treat malnutrition. In May 2016, a national web-based questionnaire was emailed to chief medical nurses in elderly care in all Swedish municipalities (n = 290). The response rate in this cross-sectional study was 75% (n = 217). Fifty per cent of the municipalities had adopted new routines, 42% had started and 8% had not. One third of the respondents considered malnutrition to be a major problem in elderly care and about half considered the new national regulation to have strengthened local work. A logistic regression showed that the odds for having adopted new routines were higher for CMNs with long experience in elderly care and who had previously worked to prevent malnutrition, and for those who considered the new national regulation helpful. To extract underlying factors in the adoption process, two principal component analyses were performed for key actors and support. For key actors, the analysis yielded four factors, explaining 67% of the total variance; (a) first line team, (b) expert team, (c) management team and (d) surrounding resources. For support, the analysis yielded three factors, which explained 65% of the total variance; (a) agile teamwork, (b) management and leadership and (c) acceptance. The slow adoption rate of the regulation raises questions about its impact; this might be an effect of the general trend of decentralisation in the Swedish welfare sector, and in elderly care in particular, making it hard to attain change that is steered centrally. However, malnutrition is a pronounced problem in elderly care and the mandatory nature of the new regulation therefore warrants further investigation of whether its launch has contributed to a reduction of malnutrition by investigating outcomes and preventive actions carried out in practice.